omgps: fix do_compile error due to uninitialized variable

The problem happended since there was an uninitialized variable
with gcc 4.9 and the parameter -Werror=maybe-uninitialized.
Initialized the variable and checked for side effects.
Removed from blacklist.

Signed-off-by: Raphael Silva <rapphil@gmail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>