use segemptyset() on signal structure before download to avoid valgrind errors.

src/plugins/auth/auth_munge.c

@@ -462,6 +462,7 @@ _decode_cred(char *m, slurm_auth_credential_t *c)
 	 *  Block all signals to allow munge_decode() to proceed
 	 *   uninterrupted. (Testing for gnats slurm/223)
 	 */
+	sigemptyset(&oset);	/* for clean valgrind */
 	sigfillset(&set);
 	sigdelset(&set, SIGABRT);
 	sigdelset(&set, SIGSEGV);

src/srun/allocate.c

@@ -76,6 +76,7 @@ allocate_nodes(void)
 	ointf  = xsignal(SIGINT,  _intr_handler);
 	otermf = xsignal(SIGTERM, _intr_handler);
 
+	sigemptyset(&oset);	/* for clean valgrind */
 	xsignal_save_mask(&oset);
 	xsignal_unblock(sigarray);