It takes ages to get bug summary from bugzilla => it is worh to
generate normal and wiki logs at the same time. Why not produce
all logs with one call

Add --commits option. Also rename --wikibugs to --bugs-wiki.

Use .wiki suffix for wiki logs. Also rename "commit-log" to "commits".
It is enough to use ".log" as the suffix.

Change-Id: I92bbc4d56a0ae9e23401be0677256059c777d712