Fix application_name's check

The old regex from the recovery.conf era (pre-v12 versions) has been kept
while the output format we parse is slightly different in v12. Since, v12, we
parse the output of "postgres -C primary_conninfo" were there is no quotes
around the whole value. Because of this, the check was reporting a wrong error
if application_name was the very first parameter appearing in primary_conninfo.

Thanks to @zeroone on github for testing and reporting this bug with details in
issue #156.

script/pgsqlms

@@ -1345,7 +1345,7 @@ sub pgsql_validate_all {
         }
 
         $guc = qx{ $POSTGRES -C primary_conninfo -D "$pgdata" $start_opts};
-        unless ($guc =~ /['\s]application_name=$nodename['\s]/) {
+        unless ($guc =~ /\bapplication_name=$nodename\b/) {
             ocf_exit_reason(
                 q{Parameter "primary_conninfo" MUST contain 'application_name=%s'. }.
                 q{It is currently set to '%s'}, $nodename, $guc );