Merge remote-tracking branch 'remotes/mdroth/tags/qga-pull-2018-11-12-tag' into staging

qemu-ga patch queue for 3.1.0

* add missing #include guards for guest-agent-core.h
* fix leaks introduced with recent win32 enablement of disk info in
  guest-get-fsinfo

# gpg: Signature made Tue 13 Nov 2018 02:52:12 GMT
# gpg:                using RSA key 3353C9CEF108B584
# gpg: Good signature from "Michael Roth <flukshun@gmail.com>"
# gpg:                 aka "Michael Roth <mdroth@utexas.edu>"
# gpg:                 aka "Michael Roth <mdroth@linux.vnet.ibm.com>"
# Primary key fingerprint: CEAC C9E1 5534 EBAB B82D  3FA0 3353 C9CE F108 B584

* remotes/mdroth/tags/qga-pull-2018-11-12-tag:
  qga: Add multiple include guard to guest-agent-core.h
  qga-win: fix leaks of build_guest_disk_info()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>