Remove auth.allowGoogleAccountUpgrade feature

Its been more than 5 years since Gerrit ran on Google AppEngine.
Assume everyone has upgraded their installations to a modern 2.x
based server, and will not need to this upgrade path enabled.

Change-Id: I9c3d7792189cd60cdf51db09eceeeb7961dd73b0
SideBySide2: Allow text selection in diff header

When displaying submodule changes, e.g.:

  -Subproject commit c0389bbf4441d290c84c0a308e710e4f21a67cd8
  +Subproject commit 9f988c6e5b1e07f66479f0d4d08537281fa4694f

permit the user to double click to select a SHA-1. This may
help them to lookup the commit in a local Git client.

Selection was disabled on Chrome/Safari as the header was part of
the table, which had previously disabled all selection. Instead
only disable selection on the patch set nav row and CodeMirror.

Change-Id: I77f7b78451331fac64958ccb255dd2cfd1900870
Merge "Remove auth.allowGoogleAccountUpgrade feature"
Merge "SideBySide2: Allow text selection in diff header"