Python 3.6 is more strict about strings containing escape sequences.
We've cleaned up other regex strings but a few sneaked back in. This
converts a few more instances to raw strings to get rid of the escape
warnings.
Change-Id: I102a3b27a2f8e55de117007b183d5c4ad40284fb
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>