Sane default for SSL on OSX

- /opt/local is not preferred anymore use /usr/local

Change-Id: I30cad4cbd28850063f26121cace05371e13bb314
BUG: 1129939
Signed-off-by: Harshavardhana <harsha@harshavardhana.net>
Reviewed-on: http://review.gluster.org/8872
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>