Give more accurate error message for dropping pinned portal

The previous code gave the same error message for attempting to drop
pinned and active portals, but those are separate states, so give
separate error messages.

src/backend/utils/mmgr/portalmem.c

@@ -464,11 +464,17 @@ PortalDrop(Portal portal, bool isTopCommit)
 
 	/*
 	 * Don't allow dropping a pinned portal, it's still needed by whoever
-	 * pinned it. Not sure if the PORTAL_ACTIVE case can validly happen or
-	 * not...
+	 * pinned it.
 	 */
-	if (portal->portalPinned ||
-		portal->status == PORTAL_ACTIVE)
+	if (portal->portalPinned)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_CURSOR_STATE),
+				 errmsg("cannot drop pinned portal \"%s\"", portal->name)));
+
+	/*
+	 * Not sure if the PORTAL_ACTIVE case can validly happen or not...
+	 */
+	if (portal->status == PORTAL_ACTIVE)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_CURSOR_STATE),
 				 errmsg("cannot drop active portal \"%s\"", portal->name)));