Properly extract the Body information of an EWS calendar item

Properly extract the Body information of an EWS calendar item

Unlike all other calendar modules, res_calendar_ews fails to extract the Body
information for a calendar item.  This is due, in part, to a quirk in the
schema in the XML - not only does a CalendarItem contain a Body element, but
the CalendarItem exists as a descendant of a different Body element.  The neon
parser was erroneously skipping all Body elements.

This patch fixes that by bypassing Body elements that are not a child of
CalendarItem, and parsing the Body element out if it is a child.

Note that the original patch by Terry Wilson only needed slight modifications
to make it properly pull the Body information out; as such, while I've linked
to the patch that I uploaded for Dmitry, I've attributed the patch to Terry.

(closes issue ASTERISK-19738)
Reported by: Dmitry Burilov
Tested by: Dmitry Burilov
patches:
  calendar_ews_body_2012_10_29.diff uploaded by Terry Wilson (license 6283)
........

Merged revisions 375528 from http://svn.asterisk.org/svn/asterisk/branches/1.8

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10@375531 65c4cc65-6c06-0410-ace0-fbb531ad65f3