Remove tabs after spaces in C comments

This was not changed in HEAD, but will be done later as part of a
pgindent run.  Future pgindent runs will also do this.

Report by Tom Lane

Backpatch through all supported branches, but not HEAD

contrib/sepgsql/uavc.c

@@ -142,7 +142,7 @@ sepgsql_avc_reclaim(void)
  * Access control decisions must be atomic, but multiple system calls may
  * be required to make a decision; thus, when referencing the access vector
  * cache, we must loop until we complete without an intervening cache flush
- * event.  In practice, looping even once should be very rare.	Callers should
+ * event.  In practice, looping even once should be very rare.  Callers should
  * do something like this:
  *
  *	 sepgsql_avc_check_valid();