Remove GIT_ANSIBLE_DEVEL token from tox.ini

It was added in an alternative attempt to install Ansible devel.
We're doing it with a constraints file now, we don't need it anymore.

Change-Id: Id15d6606ed1d2254602b576bfcef0507545010c0

tox.ini

@@ -11,9 +11,7 @@ sitepackages = True
 usedevelop = True
 install_command = pip install -U {opts} {packages} -c{env:CONSTRAINTS_FILE:/dev/null}
 setenv = VIRTUAL_ENV={envdir}
-deps =
-    #GIT_ANSIBLE_DEVEL
-    -r{toxinidir}/test-requirements.txt
+deps = -r{toxinidir}/test-requirements.txt
 
 [testenv:venv]
 commands = {posargs}