Guarantee that open routines are initialized

Open routines need to be initialized before try to open
capture or add/remove routine.

Change-Id: Ic3b88eef947ebd4a3dd2edf8120bb6bd8aec0765
Reviewed-on: https://code.wireshark.org/review/1874
Reviewed-by: Evan Huus <eapache@gmail.com>

reordercap.c

@@ -204,8 +204,6 @@ int main(int argc, char *argv[])
         exit(1);
     }
 
-    init_open_routines();
-
     /* Open infile */
     /* TODO: if reordercap is ever changed to give the user a choice of which
        open_routine reader to use, then the following needs to change. */

wiretap/file_access.c

@@ -683,6 +683,8 @@ wtap* wtap_open_offline(const char *filename, unsigned int type, int *err, char
 	gboolean use_stdin = FALSE;
 	gchar *extension;
 
+	init_open_routines();
+
 	/* open standard input if filename is '-' */
 	if (strcmp(filename, "-") == 0)
 		use_stdin = TRUE;