MFC 258063,258064,258066,258097,258185,259134:

MFC 258063,258064,258066,258097,258185,259134:
- Add an -s option to the regression tests that specifies a path to an
  alternate etcupdate.sh script to test.  This allows a non-installed
  version of the script to be tested more easily.
- Add a pre-world mode of updating similar to the -p option that can be
  passed to mergemaster.
- Fix a couple of issues with -F:
  - Fix ALWAYS_INSTALL to take precedence over the FreeBSD ID checks.
  - Fix the -F option in the case that the only upstream change is a
    change in the FreeBSD ID and the local file is removed.
- Refresh /etc/localtime after each update using tzsetup -r.
- Regenerate /var/db/services.db when /etc/services changes.

git-svn-id: svn://svn.freebsd.org/base/stable/10@259960 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f