install action fails with pip-build directory

Bug: 1179747

stable/grizzly solution not work for folsom. So at least run all
python-pip as root

Change-Id: I66b153fb186c407279317f87cc6ecd5e76dc4c4a

anvil/packaging/helpers/pip_helper.py

@@ -57,7 +57,7 @@ def uncache():
 
 def _list_installed(pip_how):
     cmd = [str(pip_how)] + FREEZE_CMD
-    (stdout, _stderr) = sh.execute(*cmd)
+    (stdout, _stderr) = sh.execute(*cmd, run_as_root=True)
     installed = []
     for line in stdout.splitlines():
         line = line.strip()