Code review comment for lp://qastaging/~jdstrand/snap-confine/seccom-arg-filtering

I forgot to mention, note that the logged seccomp denial doesn't give indication that it was an unmatched argument that caused the denial (ie, it looks that same as if 'setpriority' was missing). I'm not sure how this will impact devmode-- it would be nice to have the log show that it was an argument, but we can also handle this in snappy-debug (ie, mention that you have to use setpriority(PRIO_PROCESS, 0, >=0) or something).

This shouldn't impact this MP but thought it worth mentioning.