Successfully upgraded from 5.3.4 to 5.3.5 using the UI thanks to the new 5.3.5.4 rpms.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2015-1223.html