Another round of Coverity fixes

Additional non-security issues/improvements spotted by Coverity.

In backend/libpq, no sense trying to protect against port->hba being
NULL after we've already dereferenced it in the switch() statement.

Prevent against possible overflow due to 32bit arithmitic in
basebackup throttling (not yet released, so no security concern).

Remove nonsensical check of array pointer against NULL in procarray.c,
looks to be a holdover from 9.1 and earlier when there were pointers
being used but now it's just an array.

Remove pointer check-against-NULL in tsearch/spell.c as we had already
dereferenced it above (in the strcmp()).

Remove dead code from adt/orderedsetaggs.c, isnull is checked
immediately after each tuplesort_getdatum() call and if true we return,
so no point checking it again down at the bottom.

Remove recently added minor error-condition memory leak in pg_regress.

src/backend/libpq/auth.c

@@ -214,6 +214,7 @@ static void
 auth_failed(Port *port, int status, char *logdetail)
 {
 	const char *errstr;
+	char	   *cdetail;
 	int			errcode_return = ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION;
 
 	/*
@@ -273,17 +274,12 @@ auth_failed(Port *port, int status, char *logdetail)
 			break;
 	}
 
-	if (port->hba)
-	{
-		char	   *cdetail;
-
-		cdetail = psprintf(_("Connection matched pg_hba.conf line %d: \"%s\""),
-						   port->hba->linenumber, port->hba->rawline);
-		if (logdetail)
-			logdetail = psprintf("%s\n%s", logdetail, cdetail);
-		else
-			logdetail = cdetail;
-	}
+	cdetail = psprintf(_("Connection matched pg_hba.conf line %d: \"%s\""),
+					   port->hba->linenumber, port->hba->rawline);
+	if (logdetail)
+		logdetail = psprintf("%s\n%s", logdetail, cdetail);
+	else
+		logdetail = cdetail;
 
 	ereport(FATAL,
 			(errcode(errcode_return),

src/backend/replication/basebackup.c

@@ -227,7 +227,8 @@ perform_base_backup(basebackup_options *opt, DIR *tblspcdir)
 		/* Setup and activate network throttling, if client requested it */
 		if (opt->maxrate > 0)
 		{
-			throttling_sample = opt->maxrate * 1024 / THROTTLING_FREQUENCY;
+			throttling_sample =
+				(int64) opt->maxrate * (int64) 1024 / THROTTLING_FREQUENCY;
 
 			/*
 			 * The minimum amount of time for throttling_sample

src/backend/storage/ipc/procarray.c

@@ -2302,9 +2302,9 @@ MinimumActiveBackends(int min)
 		volatile PGXACT *pgxact = &allPgXact[pgprocno];
 
 		/*
-		 * Since we're not holding a lock, need to check that the pointer is
-		 * valid. Someone holding the lock could have incremented numProcs
-		 * already, but not yet inserted a valid pointer to the array.
+		 * Since we're not holding a lock, need to be prepared to deal with
+		 * garbage, as someone could have incremented numPucs but not yet
+		 * filled the structure.
 		 *
 		 * If someone just decremented numProcs, 'proc' could also point to a
 		 * PGPROC entry that's no longer in the array. It still points to a
@@ -2312,9 +2312,6 @@ MinimumActiveBackends(int min)
 		 * free list and are recycled. Its contents are nonsense in that case,
 		 * but that's acceptable for this function.
 		 */
-		if (proc == NULL)
-			continue;
-
 		if (proc == MyProc)
 			continue;			/* do not count myself */
 		if (pgxact->xid == InvalidTransactionId)

src/backend/tsearch/spell.c

@@ -404,7 +404,7 @@ NIAddAffix(IspellDict *Conf, int flag, char flagflags, const char *mask, const c
 		Affix->issimple = 0;
 		Affix->isregis = 1;
 		RS_compile(&(Affix->reg.regis), (type == FF_SUFFIX) ? true : false,
-				   (mask && *mask) ? mask : VoidString);
+				   *mask ? mask : VoidString);
 	}
 	else
 	{

src/backend/utils/adt/orderedsetaggs.c

@@ -585,10 +585,7 @@ percentile_cont_final_common(FunctionCallInfo fcinfo,
 	 * trouble, since the cleanup callback will clear the tuplesort later.
 	 */
 
-	if (isnull)
-		PG_RETURN_NULL();
-	else
-		PG_RETURN_DATUM(val);
+	PG_RETURN_DATUM(val);
 }
 
 /*

src/test/regress/pg_regress.c

@@ -1154,11 +1154,17 @@ get_alternative_expectfile(const char *expectfile, int i)
 {
 	char	   *last_dot;
 	int			ssize = strlen(expectfile) + 2 + 1;
-	char	   *tmp = (char *) malloc(ssize);
-	char	   *s = (char *) malloc(ssize);
+	char	   *tmp;
+	char	   *s;
 
-	if (!tmp || !s)
+	if (!(tmp = (char*) malloc(ssize)))
 		return NULL;
+	
+	if (!(s = (char*) malloc(ssize)))
+	{
+		free(tmp);
+		return NULL;
+	}
 
 	strcpy(tmp, expectfile);
 	last_dot = strrchr(tmp, '.');