providers: openid: fix exception usage
Fix two instances where the exception message was tried to
be retrieved with e.msg, where e.message is the correct name.
Also fixes an instance of an invalid bare raise when an invalid
number of days to remember authorization is specified.
Fixes: #212
Signed-off-by: Patrick Uiterwijk <puiterwijk@redhat.com>
Reviewed-by: Rob Crittenden <rcritten@redhat.com>