mangler: fix double definition of contact_flds_separator, reported from ld

(cherry picked from commit 003d87edc23f62de98a1a22db03b12ea58abcbc6)

modules/mangler/contact_ops.h

@@ -49,7 +49,7 @@
 #define DEFAULT_SEPARATOR "*"
 
 
-char *contact_flds_separator;
+extern char *contact_flds_separator;
 
 
 struct uri_format

modules/mangler/mangler.h

@@ -43,7 +43,6 @@
 
 extern regex_t *portExpression;
 extern regex_t *ipExpression;
-extern char *contact_flds_separator;
 
 
 #endif