bundled_pjproject: sip_parser: Fix return code in pjsip_find_msg

The default return code for pjsip_find_msg was PJ_SUCCESS so if
a Content-Length header wasn't found at all, pjsip_find_msg was
returning PJ_SUCCESS instead of PJSIP_EMISSINGHDR.

Also added the volatile keyword to a few variables that are used
both inside and outside the PJ_TRY/PJ_CATCH block.

Partial fix for ASTERISK_27408

Change-Id: If82ba9de921e3d57df9c68cf96ee45ccc1491f7a

third-party/pjproject/patches/0021-sip_parser-Fix-return-code-in-pjsip_find_msg-and-add.patch

+From 186f82627c40d0c3a56a6a94ce55c055ad1f7620 Mon Sep 17 00:00:00 2001
+From: George Joseph <gjoseph@digium.com>
+Date: Fri, 10 Nov 2017 09:26:29 -0700
+Subject: [PATCH] sip_parser: Fix return code in pjsip_find_msg and add
+ "volatile"
+
+The default return code for pjsip_find_msg was PJ_SUCCESS so if
+a Content-Length header wasn't found at all, pjsip_find_msg was
+returning PJ_SUCCESS instead of PJSIP_EMISSINGHDR.
+
+Also added the volatile keyword to a few variables what are used
+both insude and outsude the PJ_TRY/PJ_CATCH block.
+---
+ pjsip/src/pjsip/sip_parser.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/pjsip/src/pjsip/sip_parser.c b/pjsip/src/pjsip/sip_parser.c
+index f9a0e65b5..f65ffca5a 100644
+--- a/pjsip/src/pjsip/sip_parser.c
++++ b/pjsip/src/pjsip/sip_parser.c
+@@ -834,13 +834,13 @@ PJ_DEF(pj_status_t) pjsip_find_msg( const char *buf, pj_size_t size,
+ 				  pj_bool_t is_datagram, pj_size_t *msg_size)
+ {
+ #if PJ_HAS_TCP
+-    const char *hdr_end;
+-    const char *body_start;
++    const char *volatile hdr_end;
++    const char *volatile body_start;
+     const char *pos;
+-    const char *line;
++    const char *volatile line;
+     int content_length = -1;
+     pj_str_t cur_msg;
+-    pj_status_t status = PJ_SUCCESS;
++    volatile pj_status_t status = PJSIP_EMISSINGHDR;
+     const pj_str_t end_hdr = { "\n\r\n", 3};
+ 
+     *msg_size = size;
+-- 
+2.13.6
+