murphyif: Free the connect timer when unloading

murphyif: Free the connect timer when unloading

This fixes a crash when unloading module-murphy-ivi. Triggering the
crash probably requires that Murphy isn't running (I haven't tried
with Murphy running). The crash occurs after the module has unloaded,
and the connect timer fires - at that point the timer callback
function has been removed from the memory, so the timer callback
pointer points to invalid memory, causing a segfault when calling the
callback.

Change-Id: I78290f172eff70716491000ef9d4f37822bf3faa