make: Use rsync to keep imagelib build/src files synced up.

Using "cp -a" would create the imagelib directory correctly the first time,
but after that it would copy *into* the existing imagelib directory and create
an imagelib subdirectory. To make the copying more robust in general and to
fix this particular issue, switch to rsync.

Change-Id: Ie379c65e7c7d312dc21e24c9ce88ebda77279ac2
1 file changed