Fix ast_app_dtget() time unit inconsistency.

Note: Noone calls ast_app_dtget() with the timeout parameter of zero so
the bad code normally will never get executed.

* Fix unnecessary floating point division in func_timeout.c
timeout_write() when all other values are integers.

(closes issue ASTERISK-16817)
Reported by: Dmitry Andrianov
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Merged revisions 352029 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 352035 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@352041 65c4cc65-6c06-0410-ace0-fbb531ad65f3