Added ret initialization in os_monitering.c. During a false case, ret could have been returned without being initialized.
Added ret initialization in os_monitering.c. During a false case, ret could have been returned without being initialized.

Change-Id: Ie68e735c005b696931499093d52dfc5c9c2fadfa

01org/intel-cmt-cat,01org/intel-cmt-cat,01org/intel-cmt-cat