Revert "app_stack: Print proper exit location for PBXless channels."

Revert "app_stack: Print proper exit location for PBXless channels."

This reverts commit 617dad4cba1513dddce87b8e95a61415fb587cf1.

apps/app_stack.c: Revert buggy gosub patch

This seems to break the case when a predial macro calls a gosub.
When the gosub calls return, the Return function outputs:

app_stack.c:423 return_exec: Return without Gosub: stack is empty

This returns -1 to the calling macro, which returns to app_dial
and causes the call to hangup instead of proceeding with the macro
that invoked the gosub.

Resolves: #253
(cherry picked from commit c8f2698ec6d317cf3a97ee7053ebc4d99f313e9c)