Fix for bug https://bugzilla.redhat.com/show_bug.cgi?id=618970
The "prepare" hook is called very early in the VM statup process
before device labeling, so that it can allocate ressources not
managed by libvirt, such as DRBD, or for instance create missing
bridges and vlan interfaces.
* src/util/hooks.c src/util/hooks.h: add definitions for new hooks
VIR_HOOK_QEMU_OP_PREPARE and VIR_HOOK_QEMU_OP_RELEASE
* src/qemu/qemu_process.c: use them in qemuProcessStart and
qemuProcessStop()
This exports 3 basic routines:
- virHookInitialize() initializing the hook support by looking for
scripts availability
- virHookPresent() used to test if there is a hook for a given driver
- virHookCall() which actually calls a synchronous script hook with
the needed parameters
Note that this doesn't expose any public API except for the locations
and arguments passed to the scripts
* src/Makefile.am: add the 2 new files
* src/util/hooks.h src/util/hooks.c: implements the 3 functions
* src/libvirt_private.syms: export the 3 symbols internally
* po/POTFILES.in: add src/util/hooks.c to translatables modules
