Log Message:
Update borgbackup to 1.1.8.

Version 1.1.8 (2018-12-09)
--------------------------

Fixes:

- enforce storage quota if set by serve-command, #4093
- invalid locations: give err msg containing parsed location, #4179
- list repo: add placeholders for hostname and username, #4130
- on linux, symlinks can't have ACLs, so don't try to set any, #4044

New features:

- create: added PATH::archive output on INFO log level
- read a passphrase from a file descriptor specified in the
  BORG_PASSPHRASE_FD environment variable.

Version 1.1.7 (2018-08-11)
--------------------------

Compatibility notes:

- added support for Python 3.7

Fixes:

- cache lock: use lock_wait everywhere to fix infinite wait, see #3968
- don't archive tagged dir when recursing an excluded dir, #3991
- py37 argparse: work around bad default in py 3.7.0a/b/rc, #3996
- py37 remove loggerDict.clear() from tearDown method, #3805
- some fixes for bugs which likely did not result in problems in practice:

  - fixed logic bug in platform module API version check
  - fixed xattr/acl function prototypes, added missing ones

New features:

- init: add warning to store both key and passphrase at safe place(s)
- BORG_HOST_ID env var to work around all-zero MAC address issue, #3985
- borg debug dump-repo-objs --ghost (dump everything from segment files,
  including deleted or superceded objects or commit tags)
- borg debug search-repo-objs (search in repo objects for hex bytes or strings)

Other changes:

- add Python 3.7 support
- updated shell completions
- call socket.gethostname only once
- locking: better logging, add some asserts
- borg debug dump-repo-objs:

  - filename layout improvements
  - use repository.scan() to get on-disk order
- docs:

  - update installation instructions for macOS
  - added instructions to install fuse via homebrew
  - improve diff docs
  - added note that checkpoints inside files requires 1.1+
  - add link to tempfile module
  - remove row/column-spanning from docs source, #4000 #3990
- tests:

  - fetch less data via os.urandom
  - add py37 env for tox
  - travis: add 3.7, remove 3.6-dev (we test with -dev in master)