Re-worded table contents portion of Readme.md

Changed "usage" to "user" to match title. Also, prefixed
"pip install" with proper "sudo" command, due to command requiring
super user privelages.

Change-Id: I972bcb96fd476a4022385a418c86916038ec1aab
Signed-off-by: Kyle Schneider <kinnder@gmail.com>
Reviewed-on: http://review.gluster.org/5294
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>