Missing hyphen in git-http-backend

Add missing hyphen in the command name.
One more...
Add missing hyphen

The command is git diff --check.
Merge pull request #140 from paveljanik/patch-3

Missing hyphen in git-http-backend
Merge pull request #141 from paveljanik/patch-4

Add missing hyphen
Format username as a username not as a command

The git username was formatted as `git` instead of 'git'.
One more git user reformat

`git` -> 'git'
Format git username uniformly.
Merge branch 'patch-2' of https://github.com/paveljanik/progit2 into patch-2