webapp: Support for enabling known git repositories on ssh servers.

The repository must have been added using initremote.

Turned out to be much much simpler than expected, because I was able to
reuse the existing code for enabling rsync and gcrypt remotes, which
was already sufficiently general that it will also work for ssh remotes.
Total win!

This commit was sponsored by an unknown bitcoin contributor.

Assistant/WebApp/RepoList.hs

@@ -189,6 +189,11 @@ repoList reposelector
 				Just rr	| remoteLocationIsUrl (parseRemoteLocation rr g) ->
 					val True EnableSshGCryptR
 				_ -> Nothing
+		Just "git" -> 
+			case getconfig "location" of
+				Just loc | remoteLocationIsSshUrl (parseRemoteLocation loc g) ->
+					val True EnableSshGitRemoteR
+				_ -> Nothing
 		_ -> Nothing
 	  where
 	  	getconfig k = M.lookup k =<< M.lookup u m