Merge branch 'cb/cvsserver' into maint

"git cvsserver" had a long-standing bug in its authentication code, which has finally been corrected (it is unclear and is a separate question if anybody is seriously using it, though). * cb/cvsserver: Documentation: cleanup git-cvsserver git-cvsserver: protect against NULL in crypt(3) git-cvsserver: use crypt correctly to compare password hashes