Just a couple of Stasis-HTTP nitpick fixes.

* Fixed crash when res_stasis_http is unloaded before the
  implementation modules.
* Cleaned up test initialization for test_stasis_http.so.


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@386928 f38db490-d61c-443f-a65b-d21fe96a405b
Use the proper lower bound when doing saturation arithmetic.

16 bit signed integers have a range of [-32768, 32768).  The existing code
was using the interval (-32768, 32768) instead.  This patch fixes that.

Review: https://reviewboard.asterisk.org/r/2479/
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Merged revisions 386929 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 386930 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@386931 f38db490-d61c-443f-a65b-d21fe96a405b