recipe: Don't mount tmpfs on /live

Previously /live was the target for a tmpfs, but this is a problem with
the slightly changed mount_live() logic (probably). Therefor we remove
the tmpfs moutn (which shouldn't be needed anyway) so mount_live()
behaves correct.

Change-Id: I2b3abb2accb15bdd05e2f49e0e2881ba23c4f4bd
Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>