Re-add get_updated_changeset_revisions_from_tool_shed() method

It was accidentally removed in PR #2269.
Fix toolshed tests

lib/tool_shed/util/metadata_util.py

@@ -1,10 +1,12 @@
 import logging
+from operator import itemgetter
 
+from sqlalchemy import and_
+
+import tool_shed.util.repository_util
+from galaxy import util
 from tool_shed.util import common_util
 from tool_shed.util import hg_util
-from sqlalchemy import and_
-from operator import itemgetter
-import tool_shed.util.repository_util
 
 log = logging.getLogger( __name__ )
 
@@ -320,6 +322,23 @@ def get_updated_changeset_revisions( app, name, owner, changeset_revision ):
     return ''
 
 
+def get_updated_changeset_revisions_from_tool_shed( app, tool_shed_url, name, owner, changeset_revision ):
+    """
+    Get all appropriate newer changeset revisions for the repository defined by
+    the received tool_shed_url / name / owner combination.
+    """
+    tool_shed_url = common_util.get_tool_shed_url_from_tool_shed_registry( app, tool_shed_url )
+    if tool_shed_url is None or name is None or owner is None or changeset_revision is None:
+        message = "Unable to get updated changeset revisions from the Tool Shed because one or more of the following "
+        message += "required parameters is None: tool_shed_url: %s, name: %s, owner: %s, changeset_revision: %s " % \
+            ( str( tool_shed_url ), str( name ), str( owner ), str( changeset_revision ) )
+        raise Exception( message )
+    params = dict( name=name, owner=owner, changeset_revision=changeset_revision )
+    pathspec = [ 'repository', 'updated_changeset_revisions' ]
+    text = util.url_get( tool_shed_url, password_mgr=app.tool_shed_registry.url_auth( tool_shed_url ), pathspec=pathspec, params=params )
+    return text
+
+
 def is_downloadable( metadata_dict ):
     # NOTE: although repository README files are considered Galaxy utilities, they have no
     # effect on determining if a revision is installable.  See the comments in the