Fix/Support shallow clone for ssh protocol

[akkaradej]

I found that GitRemoteResolver is not supports shallow cloning if the source is a ssh protocol.

This is caused by

// Constructor
this._remote = url.parse(this._source);

If the source is git@bitbucket.org:foo/bar.git, it cannot find the protocol
that lead to make the condition inside _supportsShallowCloning() is always false

// _supportsShallowCloning
if (this._remote == null || this._remote.protocol == null) {
  return Q.resolve(false);
}

[sheerun]

What bower version are you using? Can you provide sample repository? I've tried git@bitbucket.org:mirror/rails.git but I get fast clone on latest Bower without this change.

[akkaradej]

I using bower 1.6.3 and this's my .bowerrc

{
  "shallow-clone-hosts": "bitbucket.org"
}

Try $ bower install git@bitbucket.org:mirror/rails.git#1-2-stable

As a bower progress:
Without this change, it downloads 351293 objects

bower progress      rails#1-2-stable Receiving objects:   2% (7026/351293), 988.00 KiB | 851.00 KiB/s

Compare wtith this change, it downloads 1293 objects

bower progress      rails#1-2-stable Receiving objects:  27% (351/1293), 540.00 KiB | 188.00 KiB/s

[sheerun]

Merged as #2506