minijail: remove 'install' target.
minijail: remove 'install' target.

Not needed, since we use portage's install tools to install instead of the
makefile target, and it's somewhat complex to get the interaction between PREFIX
and PRELOAD_PATH and DESTDIR right.

TEST=Adhoc
emerge-$board chromeos-minijail ; ls -l
/build/$board/{lib/libminijailpreload.so,sbin/minijail0}

Change-Id: I8050d514cb44361fe4e8ce3a178a0bdcae3404df
Signed-off-by: Elly Jones <1693f95ea06ee6d7b2276cb599c3f4f33a951d9c@chromium.org>
Reviewed-on: http://gerrit.chromium.org/gerrit/5989
Reviewed-by: Chris Masone <98e3d65c6b0e9e2391eb4c2e8b1e572b77e544ed@chromium.org>

omegaup/minijail,omegaup/minijail,omegaup/minijail,omegaup/minijail