Recent change in Gevent version 1.5.0 requires Alpine packages
file, make, libffi-dev to build the wheel. Repair the broken
build by adding these packages to the Dockerfile. Also see
https://github.com/gevent/gevent/issues/1555
Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>
Change-Id: I5ec970f6f0b5594be5ac9f1abd693df098df749c