we will default to callie

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@6557 d0543943-73ff-0310-b7d9-9358b9ac24b2

conf/lang/en/en.xml

 <include>
-  <language name="en" sound-path="/snds" tts-engine="cepstral" tts-voice="david">
+  <language name="en" sound-path="/snds" tts-engine="cepstral" tts-voice="callie">
     <X-PRE-PROCESS cmd="include" data="demo/demo.xml"/>
     <!--voicemail_en_tts is purely implemented with tts, we need a files based implementation too -->
     <X-PRE-PROCESS cmd="include" data="vm/tts.xml"/>