Add jacobhobbie@google.com to trust owners.

With cbrubaker and vishwath leaving Google soon, someone should own this. jacobhobbie has done the most active work with the trust code recently and seems appropriate

Change-Id: Icf3d411f9f4acfc7af28829efa061b02a997f6d4
Merged-In: Icf3d411f9f4acfc7af28829efa061b02a997f6d4
(cherry picked from commit 71b6b8eb)