All-in-1 decentralized project management git+tickets+wiki
Also, check out veracity. New kid on the block, but has bug tracking and project management built in.
http://veracity-scm.com/
I found one answer, but it has its own version control system built-in.
"Fossil SCM offers decentralized source control, tickets and a wiki: http://www.fossil-scm.org/"
P.S. : I love how so down votes like crazy ,even if there are tons of same type of questions with lots of up votes, just because they do not get the idea.
I'd suggest using tools that work together and each do one thing well rather than a tool that attempts to do everything. That way, you're less locked in to your tool choice: if you find that one of the tools isn't doing it for you, you can easily swap it out and continue to use the other tools you're used to.
There are a few decentralised project tracking tools that build upon distributed version control for their storage. I myself have written one: https://github.com/npryce/deft.
I also did a quick review of other tools in the same space that I found: https://github.com/npryce/deft/wiki/Other-Distributed-Issue-Trackers. This may well be out of date now.