dep: add refs to the fizzy-saas git dependencies

so that we can quickly switch the app between using the saas extension
and not. (Bundler will re-fetch the remote if the ref is not present.)

Also set the bundler config to auto-install missing dependencies.

Gemfile.lock

@@ -1,6 +1,7 @@
 GIT
   remote: https://github.com/basecamp/file_repository
   revision: 8c8d1594f3ec7e8c0938e6a7f7def521692344e4
+  ref: 8c8d1594f3ec7e8c0938e6a7f7def521692344e4
   specs:
     file_repository (1.4.6)
 
@@ -14,6 +15,7 @@ GIT
 GIT
   remote: https://github.com/basecamp/portfolio
   revision: 86411a53d19a42ce44705a50ebe7c22828597991
+  ref: 86411a53d19a42ce44705a50ebe7c22828597991
   specs:
     portfolio (5.2.0)
       activesupport
@@ -22,6 +24,7 @@ GIT
 GIT
   remote: https://github.com/basecamp/queenbee-plugin
   revision: eb01c697de1ad028afc65cc7d9b5345a7a8e849f
+  ref: eb01c697de1ad028afc65cc7d9b5345a7a8e849f
   specs:
     queenbee (3.2.0)
       activeresource
@@ -31,6 +34,7 @@ GIT
 GIT
   remote: https://github.com/basecamp/queuety
   revision: bf7e2a552fb674533d3e092f06dbf9b5d1ebc753
+  ref: bf7e2a552fb674533d3e092f06dbf9b5d1ebc753
   branch: rails4
   specs:
     queuety (4.0.2)
@@ -48,6 +52,7 @@ GIT
 GIT
   remote: https://github.com/basecamp/service_concurrency_prevention
   revision: 320da99431718615ed86f8723e8b9d3259c602a3
+  ref: 320da99431718615ed86f8723e8b9d3259c602a3
   specs:
     service_concurrency_prevention (1.1.1)
       activesupport
@@ -55,6 +60,7 @@ GIT
 GIT
   remote: https://github.com/basecamp/signal_id
   revision: d6c2a5ceed7bb57bf7dcdebdb439e7cd526fca09
+  ref: d6c2a5ceed7bb57bf7dcdebdb439e7cd526fca09
   branch: rails4
   specs:
     signal_id (4.3.2)
@@ -85,6 +91,7 @@ GIT
 GIT
   remote: https://github.com/jeremy/mysql2.git
   revision: b5766f5d296745d6aed014c8c0b7d82ef149ade1
+  ref: b5766f5d296745d6aed014c8c0b7d82ef149ade1
   branch: force_latin1_to_utf8
   specs:
     mysql2 (0.5.4.latin1utf8)