CHOP-955, CHOP-957: Prioritize indra.util.llmanifest in same source repo.

It seems that certain build hosts have an (obsolete? broken?) install of
indra.util.llmanifest under the system Python. If we append the local repo
indra/lib/python to sys.path, viewer_manifest.py pulls in the broken
llmanifest. Prepend to sys.path instead to ensure we get the right one.

indra/newview/viewer_manifest.py

@@ -34,8 +34,10 @@
 import time
 import random
 viewer_dir = os.path.dirname(__file__)
-# add indra/lib/python to our path so we don't have to muck with PYTHONPATH
-sys.path.append(os.path.join(viewer_dir, os.pardir, "lib", "python"))
+# Add indra/lib/python to our path so we don't have to muck with PYTHONPATH.
+# Put it FIRST because some of our build hosts have an ancient install of
+# indra.util.llmanifest under their system Python!
+sys.path.insert(0, os.path.join(viewer_dir, os.pardir, "lib", "python"))
 from indra.util.llmanifest import LLManifest, main, proper_windows_path, path_ancestors
 try:
     from llbase import llsd