buildroot

package/erlang-lager: add .hash file

Similar to jquery-keyboard, it seems the erlang-lager tarball on the
autobuilder is corrupt.  Fix it by adding a .hash file so it falls back to our
s.b.o mirror.

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>