MFH r336801,r336854:

MFH r336801 (cem):
Cherry-pick upstream 2c8c83b9

Relevant vendor changes:
Fix issue #948: out-of-bounds read in lha_read_data_none()

MFH r336854:
Sync libarchive with vendor.

Important vendor changes:
PR #993: Chdir to -C directory for metalog processing
OSS-Fuzz #4969: Check size of the extended time field in zip archives
PR #973: Record informational compression level in gzip header

amdbugs: 877
Security: CVE-2017-14503

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFV r248590,248594:
Update libarchive to 3.1.2

Some of new features:
- support for lrzip and grzip compression
- support for writing tar v7 format
- b64encode and uuencode filters
- support for __MACOSX directory in Zip archives
- support for lzop compresion (external utility)

Update libarchive's vendor dist to version 3.1.2 from release branch.

Git branch: release
Git commit: 19f23e191f9d3e1dd2a518735046100419965804

Obtained from: https://github.com/libarchive/libarchive.git