Remove unused return value from check_percona_api_version()

There is no user of this return value and furthermore the function can
only ever return true.

src/include/utils/percona.h

@@ -14,16 +14,13 @@
 
 extern const PGDLLIMPORT int percona_api_version;
 
-static inline bool
+static inline void
 check_percona_api_version(void)
 {
 	if (PERCONA_API_VERSION != percona_api_version)
 	{
 		elog(FATAL, "Percona API version mismatch, the extension was built against a different PostgreSQL version!");
-		return false;
 	}
-
-	return true;
 }
 
 #endif