Ignore blank lines in pgindent exclude files

Currently a blank line matches everything, which is almost never what
someone would want. If they really want that they can use a wildcard
regex to do it.

Author: Zsolt Parragi <zsolt.parragi@percona.com>

Discussion: https://postgr.es/m/CAN4CZFNka+2q3=-Dithr4w65RJfwPaV92T62spEzLn+T4MgcMg@mail.gmail.com

src/tools/pgindent/pgindent

@@ -182,7 +182,7 @@ sub process_exclude
 		while (my $line = <$eh>)
 		{
 			chomp $line;
-			next if $line =~ m/^#/;
+			next if $line =~ m/^#/ || $line eq "";
 			my $rgx = qr!$line!;
 			@files = grep { $_ !~ /$rgx/ } @files if $rgx;
 		}