staging: lustre: mgc: fix 'error handling' issues

Fix 'error handling' issues found by Coverity version 6.6.1:
Unchecked return value (CHECKED_RETURN)
Calling function without checking return value.
Argument cannot be negative (NEGATIVE_RETURNS)
Negative value used as argument to a function expecting a
positive value.
Signed-off-by: NSebastien Buisson <sbuisson@ddn.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4055
Reviewed-on: http://review.whamcloud.com/7842Reviewed-by: NDmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: NJames Nunez <james.a.nunez@intel.com>
Reviewed-by: NOleg Drokin <oleg.drokin@intel.com>
Signed-off-by: NJames Simmons <jsimmons@infradead.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/mgc/mgc_request.c

@@ -502,8 +502,12 @@ static void do_requeue(struct config_llog_data *cld)
 	 */
 	down_read(&cld->cld_mgcexp->exp_obd->u.cli.cl_sem);
 	if (cld->cld_mgcexp->exp_obd->u.cli.cl_conn_count != 0) {
+		int rc;
+
 		CDEBUG(D_MGC, "updating log %s\n", cld->cld_logname);
-		mgc_process_log(cld->cld_mgcexp->exp_obd, cld);
+		rc = mgc_process_log(cld->cld_mgcexp->exp_obd, cld);
+		if (rc && rc != -ENOENT)
+			CERROR("failed processing log: %d\n", rc);
 	} else {
 		CDEBUG(D_MGC, "disconnecting, won't update log %s\n",
 		       cld->cld_logname);