recovery: fix --update_package using legacy path

When using legacy path, recovery will not be able to mount the
correct device. Fix by resolving the symlink before installing.

Change-Id: Ibb268908458c49de09204a1a0ba3143e83ccc0c4
Merge "recovery: fix --update_package using legacy path" into cm-10.2
Revert "recovery: fix --update_package using legacy path"

Backing this out for now to prevent a tragic recovery loop
where it'll keep restarting to flash from /cache/recovery/command
and crash from signature verification bug. The loop can only
be ended by removing the command file via adb.

This reverts commit ca028615e43fe09c3dcceeb47ca8cf3ceb08c2b4.

Change-Id: Iea29ee04871e136c680df699f5d19570aba44113
Merge "Revert "recovery: fix --update_package using legacy path"" into cm-10.2
Merge branch 'cm-10.2' into martincz