lp1466201 Disable Google Analytics in the staff client

lp1466201 Disable Google Analytics in the staff client

As Galen Charlton noted in bug 1452883, "I suggest disabling Google Analytics
outright in the staff client; there's far too much potential for leaking patron
information." This branch aims to do so.

Test plan: Enable Google Analytics in config.tt2. Access the catalog in the
staff client. Click Debug to view the source code. Pre-patch, you'll see
the Google Analytics javascript within the head element. Post-patch, that
javascript will be gone. Viewing the source of a catalog page in a browser
should continue to show the Google Analytics javascript within the head element.

Signed-off-by: Kathy Lussier <klussier@masslnc.org>
Signed-off-by: Ben Shum <bshum@biblio.org>