fix new[]/delete mismatch

As seen by ooo90105-1.ods with memcheck

Conflicts:
	sc/source/filter/xml/xmldpimp.cxx

Change-Id: Ib976632aa52556132b3d05ebb33e8fb64d8d9890
Reviewed-on: https://gerrit.libreoffice.org/9716
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>