Fix uninitialised read in apmlActiveMonitor

[illiav-j]

Fixes the error when trying to build on the latest OpenBMC:

| ../git/src/main.cpp: In function 'apmlActiveMonitor()':
| ../git/src/main.cpp:693:16: error: 'ret' is used uninitialized [-Werror=uninitialized]
|   693 |     while (ret != OOB_SUCCESS)
|       |            ~~~~^~~~~~~~~~~~~~
| ../git/src/main.cpp:689:18: note: 'ret' was declared here
|   689 |     oob_status_t ret;
|       |                  ^~~

This change has not been tested.

[ojayanth]

@abinayaddhandapani Can you please add the requeste changes in next refersh?