Don't use the dashed for of git commands

Don't use the dashed for of git commands

With the release of git 1.6.0, the dashed forms of the git commands
are no longer installed in $PATH by default, so trying to use them is
likely to fail. This patch replaces all remaining dashed git calls by
their dashless equivalents -- even in comments and docs, for
consistency and to aid grepping.

Signed-off-by: Karl Hasselström <kha@treskal.com>