[Libvirt-cim] [PATCH 0 of 3] [RFC] Add external migration checks

This set adds external check support to VSMigration service Any executable in the MIG_CHECK_DIR is executed during the CheckVSIsMigratable() method. If it returns 0, the check continues, nonzero and an error is reported to the client. If the client puts anything in the CheckParams[] field, the method writes these out to a temporary file and passes the filename on the command-line to the check programs. Migration checks are given MIG_CHECK_TIMEOUT (=10 sec by default) to get their business done, otherwise they are killed and we report failure. This avoids letting the checks block the CIMOM for too long. Comments appreciated.