PGPRO-10866: Add static decoration to avoid error:

"no previous extern declaration for non-static variable [-Wmissing-variable-declarations]".

Return back changes from the similar commit
d01ea74 (PGPRO-10866: Add static decoration to
avoid error) as they were reverted in the commit
c927d0c (Add progress bar during query
execution to track progress. (#63)).

Author: Marina Polyakova

pg_query_state.c

@@ -101,8 +101,8 @@ static List *GetRemoteBackendQueryStates(PGPROC *leader,
 										 ExplainFormat format);
 
 /* Shared memory variables */
-shm_toc			   *toc = NULL;
-RemoteUserIdResult *counterpart_userid = NULL;
+static shm_toc			  *toc = NULL;
+static RemoteUserIdResult *counterpart_userid = NULL;
 pg_qs_params	   *params = NULL;
 shm_mq			   *mq = NULL;