Remove duplicate prototype declaration. (issue #9517 reported by junky)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@61375 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -1405,7 +1405,6 @@ static const struct cfsubscription_types *find_subscription_type(enum subscripti
 static int __sip_show_channels(int fd, int argc, char *argv[], int subscriptions);
 static int sip_show_channels(int fd, int argc, char *argv[]);
 static int sip_show_subscriptions(int fd, int argc, char *argv[]);
-static int __sip_show_channels(int fd, int argc, char *argv[], int subscriptions);
 static char *complete_sipch(const char *line, const char *word, int pos, int state);
 static char *complete_sip_peer(const char *word, int state, int flags2);
 static char *complete_sip_show_peer(const char *line, const char *word, int pos, int state);