Use the correct root_id when composing the activity Admin screen

Activity comments have the root_id of the root parent item, while non-comments
have their own ID as the root_id. Setting this value correctly ensures that the
correct data is sent with AJAX comment creation, which in turn ensures that
comments are associated with the correct activity item.

Fixes #5014

git-svn-id: https://buddypress.svn.wordpress.org/trunk@7579 cdf35c40-ae34-48e0-9cc9-0c9da1808c22
Use the correct function to create timestamp permalinks in Activity admin

The previous method of concatenating activity permalink URLs did not account
for activity comments, which do not have their own permalinks but instead
appear on the permalink pages of their root parents.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@7580 cdf35c40-ae34-48e0-9cc9-0c9da1808c22