build tweak

git-svn-id: http://svn.openzap.org/svn/openzap/trunk@630 a93c3328-9c30-0410-af19-c9cd2b2d52af

libs/openzap/mod_openzap/mod_openzap.c

@@ -2174,7 +2174,7 @@ SWITCH_STANDARD_API(oz_function)
 	} else if (!strcasecmp(argv[0], "q931_pcap")) {
 		int32_t span_id = 0;
                 zap_span_t *span;
-		char *pcapfn = NULL;
+		const char *pcapfn = NULL;
 		char *tmp_path = NULL;
 
                 if (argc < 3) {