conn_init: set unused attribute for unused param

pEndOfCfg is unused, and self assigning is an error
(with Werror) in Clang. Set this parameter as unused instead.

Change-Id: Ifea8a44579ef842ceed4837791a5a5142d0e3bc4
Merge "conn_init: set unused attribute for unused param"
Merge remote-tracking branch 'google/master' into linaro_android_4.3.1