`magit-insert-status-remote-line': define using `magit-define-inserter'

Among other things, commit f6506846 renamed `magit-svn-remote-string'
to `magit-svn-insert-status-remote-line', and added it to
`magit-after-insert-remote-line-hook', intending for it to run after
`magit-insert-status-remote-line'.

However, this could never work, since `magit-insert-status-remote-line'
wasn't defined using `magit-define-inserter' meaning the hook wouldn't exist,
and even if did, it would be called `magit-after-insert-STATUS-remote-line-hook'.

As a result, `magit-svn-mode` no longer displayed the "Remote:" line.

I would have liked to drop the "status" part in `magit-insert-status-remote-line'
(see commit 44abd449), but then I'd have to satisfy my urge to make the same
change(s) in *all* the inserter functions, thereby tainting this branch with
commits that don't belong, so I've opted to adjust `magit-svn-mode' instead.

Choices, choices...

Fixes #924.

Signed-off-by: Pieter Praet <pieter@praet.org>
`magit-insert-svn-{unpulled,unpushed}': pass STYLE arg to `magit-wash-log'

Commit 4966a044 altered `magit-parse-log-line' to no longer set STYLE
if it was nil, because `magit-wash-log' is now supposed to always pass
it an appropriate value (via `magit-wash-log-line').

`magit-insert-svn-{unpulled,unpushed}' weren't updated accordingly though,
causing `magit-svn-mode` to fail with `wrong-number-of-arguments` when
there are unpulled/unpushed commits.

Fixes #925.

Signed-off-by: Pieter Praet <pieter@praet.org>
Merge pull request #926 from praet/svn

SVN fixes