git-prompt.sh: make $f local to __git_eread()
git-prompt.sh: make $f local to __git_eread()

This function uses (non-local) $f to store the value of its first parameter.
This can interfere with the user's environment.

Signed-off-by: Justin Guenther <02c9c2559ec57be99992330c995a6c0b767b6328@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git