Move ansible installation from pre_command to install phase in tox

We currently install ansible during the pre_command phase in tox. This
breaks the following use case:

  tox -e py36 --notest
  ttrun <test case>

This is broken now because ttrun doesn't run pre_commands. Instead we
already have a pip wrapper that does the nodeenv installation. We can
use this to also call zuul-manage-ansible on zuul installation.

Change-Id: I680777e5406368d35366602ac37e029db91c8a5c

tools/pip.sh

@@ -38,3 +38,8 @@ then
     popd
 fi
 pip install $*
+
+# Check if we're installing zuul. If so install the managed ansible as well.
+if echo "$*" | grep -vq requirements.txt; then
+    zuul-manage-ansible -v
+fi

tox.ini

@@ -25,7 +25,6 @@ install_command = pip install {opts} {packages}
 whitelist_externals = bash
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands_pre = zuul-manage-ansible -v
 commands = stestr run {posargs}
            stestr slowest
 
@@ -82,7 +81,6 @@ install_command = {[nodeenv]install_command}
 commands = stestr run --concurrency=1 --test-path ./tests/nodepool {posargs}
 
 [testenv:remote]
-commands_pre = zuul-manage-ansible -v
 commands = stestr run --test-path ./tests/remote {posargs}
 passenv = ZUUL_TEST_ROOT OS_STDOUT_CAPTURE OS_STDERR_CAPTURE OS_LOG_CAPTURE OS_LOG_DEFAULTS ZUUL_REMOTE_IPV4 ZUUL_SSH_KEY NODEPOOL_ZK_HOST
 install_command = {[nodeenv]install_command}