Moved pkg pubspecs to use dev_dependencies where appropriate

BUG=https://code.google.com/p/dart/issues/detail?id=9309

Review URL: https://codereview.chromium.org//12962003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@20285 260f80e4-7a28-3924-810f-c04153c831b5
diff --git a/pubspec.yaml b/pubspec.yaml
index ae3d11d..f531f46 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -6,7 +6,6 @@
   behalf of a user, and making authorized HTTP requests with the user's
   OAuth2 credentials.
 dependencies:
-  unittest:
-    sdk: unittest
-  http:
-    sdk: http
+  http: any
+dev_dependencies:
+  unittest: any