Fix incorrect sizeof() usage in features.c.

Fix incorrect sizeof() usage in features.c.

This didn't actually result in a bug anywhere, luckily.  The only place
where the result of these memcpys was used is in app_dial, and the only
field that it read out of ast_call_feature was the first one, which is an
int, so these memcpys always copied just enough to avoid a problem.
........

Merged revisions 359069 from http://svn.asterisk.org/svn/asterisk/branches/1.8

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10@359072 65c4cc65-6c06-0410-ace0-fbb531ad65f3