dedupe: backup & restore selinux contexts.
When use dup format, skip generate *.context file.

Change-Id: I131c69c8e81e0c0ff40bf75dd7e27a0bdec54615
dedupe: fix BUILD_HOST_EXECUTABLE.

Change-Id: I06945a71699b91935ae0857a59bffeae72e9d47a
Merge https://github.com/xiaolu/android_bootable_recovery into xiaolu_cm-11.0

Conflicts:
	dedupe/dedupe.c