aries-common: updater: fix install from external sd

Don't use -f with readlink since it won't work if
the destination does not exist.

Change-Id: I1e2f16ba009108dbdc69f91202c1dd071c1361e7
aries-common: set TARGET_ARCH_LOWMEM

Change-Id: I3955d2a723d538f56426882b33121256f305b9fd
aries-common: rename Camera -> Gallery2 overlay

Change-Id: I1d214abffd49f908377d067d2b3f9b1dbf2021dd
Revert "aries-common: symlink /external_sd instead of /emmc in recovery"

This reverts commit 498917672bfc93b5abefc94b93a116c884e59bb7.