recovery: only use vold format for exact path match

Otherwise when formatting /sdcard/.android_secure, it will be
matched to /sdcard and vold will format the entire /sdcard.

Change-Id: Ifc26121f982b391b4ccf582b6162ab76feb72cae
recovery: don't overallocate for get_android_secure_path

We simply need the space to fill both strings and a final null.

a char pointer is a lot larger than a char ;)

Change-Id: I3472e1a9978fb2f6d439d4af9c072a98cec0cd19
Merge remote-tracking branch 'github/cm-10.2' into mackay-cm102