segfault in DEMConvert

Description

segfault when calling DEMConvert with extended filename.

Found during code review of !179 (merged)

Steps to reproduce

/bin/otbcli_DEMConvert -in "/home/poughov/cnes/dev/otb-data/Input/ToulouseExtract_WithGeom.tif?&skipgeom=true&skipcarto=true" -out blabla.tif

Configuration information

OTB develop