PJSIP: Prevent crash no-URI contacts

This prevents a crash from occurring when a contact with no URI is used
for the creation of an outbound out-of-dialog request with no
associated endpoint.
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Merged revisions 420949 from http://svn.asterisk.org/svn/asterisk/branches/12
........

Merged revisions 420950 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@420953 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_pjsip.c

@@ -2285,7 +2285,7 @@ static int create_out_of_dialog_request(const pjsip_method *method, struct ast_s
 	pjsip_tpselector selector = { .type = PJSIP_TPSELECTOR_NONE, };
 
 	if (ast_strlen_zero(uri)) {
-		if (!endpoint && !contact) {
+		if (!endpoint && (!contact || ast_strlen_zero(contact->uri))) {
 			ast_log(LOG_ERROR, "An endpoint and/or uri must be specified\n");
 			return -1;
 		}