Stop installing test-requirements with projects

This is a test of installing openstack and then seeing if it works.
OpenStack components do not need test-requirements to operate,
that's why they are test-requirements.

Additionally, as we look forward to depsolver pip, this is going
to screw us because we don't apply constraints to linters, which
are expressed in - you guessed it, test-requirements.

Change-Id: I8f24b839bf42e2fb9803dc7df3a30ae20cf264eb
(cherry picked from commit 09b5b05c47)
(cherry picked from commit d3ab04bcb1)
(cherry picked from commit 6a500ad269)

inc/python

@@ -349,13 +349,6 @@ function pip_install {
 
     $xtrace
 
-    # Also install test requirements
-    local install_test_reqs=""
-    local test_req="${package_dir}/test-requirements.txt"
-    if [[ -e "$test_req" ]]; then
-        install_test_reqs="-r $test_req"
-    fi
-
     # adding SETUPTOOLS_SYS_PATH_TECHNIQUE is a workaround to keep
     # the same behaviour of setuptools before version 25.0.0.
     # related issue: https://github.com/pypa/pip/issues/3874
@@ -365,7 +358,7 @@ function pip_install {
         no_proxy="${no_proxy:-}" \
         PIP_FIND_LINKS=$PIP_FIND_LINKS \
         SETUPTOOLS_SYS_PATH_TECHNIQUE=rewrite \
-        $cmd_pip $upgrade $install_test_reqs \
+        $cmd_pip $upgrade \
         $@
     result=$?