core: update INSTALL file.

Change-Id: Ie6f041810da647e39d4bbb5384f51dadd6f69b30
Signed-off-by: hchiramm <hchiramm@redhat.com>
Reviewed-on: http://review.gluster.org/8573
Reviewed-by: Prashanth Pai <ppai@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>