Bug 611790 - fix coverify Defect Type: Null pointer dereferences issues 11940 - 12166

https://bugzilla.redhat.com/show_bug.cgi?id=611790
Resolves: bug 611790
Bug description: Fix coverify Defect Type: Null pointer dereferences issues 11940 - 12166
Fix description: Catch possible NULL pointer in ldapu_cert_mapfn_default().

lib/ldaputil/certmap.c

@@ -1221,6 +1221,7 @@ static int ldapu_cert_mapfn_default (void *cert_in, LDAP *ld,
 
 	if (rdns == NULL) {
 	    /* error */
+	    return LDAPU_ERR_INTERNAL;
 	}
     
 	/* find last RDN */