[omemo] Update CHANGELOG & manifest.ini

omemo/CHANGELOG

+2.3.8 / 2017-10-07
+- Bug Fixes
+
 2.3.7 / 2017-08-26
 - Query only the most recent PEP items
 

omemo/manifest.ini

 [info]
 name: OMEMO
 short_name: omemo
-version: 2.3.7
+version: 2.3.8
 description: OMEMO is an XMPP Extension Protocol (XEP) for secure multi-client end-to-end encryption based on Axolotl and PEP. You need to install some dependencys, you can find install instructions for your system in the Github Wiki.
 authors: Bahtiar `kalkin-` Gadimov <bahtiar@gadimov.de>
  Daniel Gultsch <daniel@gultsch.de>