Exceptions: finish sentence with fullstop

Commit 5936b2158da16bc0dbcaa99d5009a76f077999d7 added an exception
that was terminated by a comma instead of a full stop.

TrivialFix

Change-Id: I05ee9d9a0a68eeb41fa66b6ec5ad7522eb5c386a
Merge "Exceptions: finish sentence with fullstop"