patch: fix CVE-2018-1000156

patch: fix CVE-2018-1000156

* CVE detail: https://nvd.nist.gov/vuln/detail/CVE-2018-1000156

* upstream tracking: https://savannah.gnu.org/bugs/index.php?53566

* Fix arbitrary command execution in ed-style patches:
  - src/pch.c (do_ed_script): Write ed script to a temporary file instead
    of piping it to ed: this will cause ed to abort on invalid commands
    instead of rejecting them and carrying on.
  - tests/ed-style: New test case.
  - tests/Makefile.am (TESTS): Add test case.

(From OE-Core rev: 6b6ae212837a07aaefd2b675b5b527fbce2a4270)

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>