Always free network and graphics cookies

Always free network and graphics cookies

qemuMigrationEatCookie has flags to control if these should
be parsed, but it does not fill mig->flags. These cookies might
get leaked if these flags are not set by qemuMigrationBakeCookie.

42 (32 direct, 10 indirect) bytes in 1 blocks are definitely lost in
loss record 361 of 662
==123== by 0x1BA33FCA: qemuMigrationEatCookie (qemu_migration.c:678)
==123== by 0x1BA34A1E: qemuMigrationRun (qemu_migration.c:3108)
==123== by 0x1BA3622B: doNativeMigrate (qemu_migration.c:3343)
==123== by 0x1BA3B408: qemuMigrationPerform (qemu_migration.c:4138)