tree ab2062b250167e1abb19fbd8aebb6c6ab02eed26
parent 9a492d5e87935fa698b5729a35ab44fe0fc28069
author Fabio Utzig <utzig@apache.org> 1579099071 -0300
committer Fabio Utzig <utzig@utzig.org> 1579165894 -0300

imgtool: update a few errors to use click's

Click has better UI for exceptions, so instead of throwing a backtrace,
allow it to print a nicer error message.

Signed-off-by: Fabio Utzig <utzig@apache.org>