Most of our code base uses space after comma but not before;
fix the remaining uses before adding a syntax check.

* src/network/bridge_driver.c: Consistently use commas.
* src/node_device/node_device_hal.c: Likewise.
* src/node_device/node_device_udev.c: Likewise.
* src/storage/storage_backend_rbd.c: Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>