KVM/libvirt/Review libvirt error messages in journald

Errors:
 * Cannot allocate memory
 * No space left on device
 * Failed to get shared "write" lock
 * Operation failed: Storage source conflict with pool
 * internal error:
 * qemu unexpectedly closed the monitor
 * End of file from qemu monitor
 * connection closed due to keepalive timeout
 * process exited while connecting to monitor
 * End of file while reading data: Input/output error
 * Failed to acquire pid file
 * argument unsupported
 * Operation not supported


 * unknown procedure
 * Unable to read from monitor: Connection reset by peer