move "install zip from sideload" to installation submenu

* Also includes the below commit:

fix installation from internal sdcard

bug introduced in previous commit

Change-Id: If41d409801e9a58df9515ac783bf503f80909d3e

* I've done some minor changes to the original commit,
  which includes but is not limited to moving the
  "install zip from sideload" above "/sdcard/update.zip".

Signed-off-by: Chirayu Desai <cdesai@cyanogenmod.org>
Change-Id: I27a763a0d41085719a6c7d9c3b8a20fbcae4b072