Fix hub am for Enterprise URLs

Still won't work for Enterprise gists, but this makes it work for pull
request & commit URLs.

Fixes mislav#584

Author: mislav

features/am.feature

@@ -0,0 +1,29 @@
+Feature: hub am
+  Scenario: Enterprise repo
+    Given I am in "git://git.my.org/mislav/dotfiles.git" git repo
+    And I am "mislav" on git.my.org with OAuth token "FITOKEN"
+    And "git.my.org" is a whitelisted Enterprise host
+    Given the GitHub API server:
+      """
+      get('/api/v3/repos/mislav/dotfiles/pulls/387') {
+        halt 400 unless request.env['HTTP_ACCEPT'] == 'application/vnd.github.v3.patch'
+        <<PATCH
+From 7eb75a26ee8e402aad79fcf36a4c1461e3ec2592 Mon Sep 17 00:00:00 2001
+From: Mislav <[email protected]>
+Date: Tue, 24 Jun 2014 11:07:05 -0700
+Subject: [PATCH] Create a README
+---
+diff --git a/README.md b/README.md
+new file mode 100644
+index 0000000..ce01362
+--- /dev/null
++++ b/README.md
++hello
+-- 
+1.9.3
+PATCH
+      }
+      """
+    When I successfully run `hub am -q -3 https://git.my.org/mislav/dotfiles/pull/387`
+    And I successfully run `git log -1 --format=%s`
+    Then the output should contain exactly "Create a README\n"

lib/hub/commands.rb

@@ -498,15 +498,19 @@ def cherry_pick(args)
     # ... downloads patch via API ...
     # > git am /tmp/55.patch
     def am(args)
-      if url = args.find { |a| a =~ %r{^https?://(gist\.)?github\.com/} }
-        idx = args.index(url)
-        if $1 == 'gist.'
-          path_parts = $'.sub(/#.*/, '').split('/')
-          gist_id = path_parts.last
+      gh_url = nil
+      idx = args.index { |arg|
+        gh_url = if arg =~ %r{^https?://gist\.github\.com/} then URI(arg)
+        else resolve_github_url(arg)
+        end
+      }
+
+      if gh_url
+        if "gist.github.com" == gh_url.host
+          gist_id = gh_url.path.split('/').last
           patch_name = "gist-#{gist_id}.txt"
           patch = api_client.gist_raw(gist_id)
         else
-          gh_url = resolve_github_url(url)
           case gh_url.project_path
           when /^pull\/(\d+)/
             pull_id = $1.to_i