FAQ: Add section about different packaging strategies for libguestfs.
ocaml: Rewrite TESTS rule to be compatible with automake 1.13 parallel-tests.

Because of this bug in automake:

  https://lists.gnu.org/archive/html/bug-automake/2013-01/threads.html#00103

this requires that we duplicate the lists of bytecode (bc) and native
code (opt) tests because we cannot use ordinary GNU make macros to
construct these lists.
tests/data: Add some blank disks in various sizes and formats for testing.
tests: Better testing of guestfs_disk_* functions using blank disks from tests/data directory.
tests/c-api: Remove 'GETKEY:' hack since it's no longer used anywhere.
Revert "tests: Add a regression test for all disk_* info commands (RHBZ#981663)."

This reverts commit 2311fb0632a64cfa2bab8bf65c82ffaa042d619e.

This is no longer needed, since now the disk_* info functions
are being properly tested by the C API tests.
New API: add-drive-scratch.

This adds a temporary scratch drive to the handle.
tests/c-api: Use guestfs_add_drive_scratch API to create scratch drives.

Replaces the old custom code for making and deleting the drives.
tests/lvm: Remove some commented out debugging code.
fish: Link to the new 'scratch' command from the old 'sparse' command.
tests: Use new guestfs_add_drive_scratch API where possible in tests.

Replaces code such as:

  fd = open "test1.img"
  ftruncate fd, size
  close fd
  g.add_drive "test1.img"

with the shorter and simpler:

  g.add_drive_scratch size