fetch: Print full url in header

Do not remove "/" and ".git" from the end of the header url when
fetching. This affects the output of "fetch" and "fetch --prune"
making the header url more consistent with "remote --verbose".

Add tests to verify that "fetch" and "fetch --prune" do not strip the
trailing characters from the header url.

Output before this patch:

    $ git fetch remote-with-dot-git-and-slash
    From https://github.com/git/git
       a155a5f..5512ac5  maint      -> upstream/maint

Output after this patch:

    $ git fetch remote-with-dot-git-and-slash
    From https://github.com/git/git.git/
       a155a5f..5512ac5  maint      -> upstream/maint

Signed-off-by: Tom Miller <jackerran@gmail.com>