This patch set cleans up the current implementation of pegleg. As
all the git exceptions inconsistently inits or override the message.
This also cleans up a handful of incorrect kwarg keywords, and improve
handling of the exception messages.
Change-Id: I438eb032728c71cbf972c2120a76d06106cb1580
Signed-off-by: Tin Lam <tin@irrational.io>