Module which generates QGIS descriptor is called Qgis while the source directory is QGIS (upper case)
I think that directory and module names in OTB are case sensitive and directory names match the name of the corresponding module. It is not the case for the QGIS wrapper module
Note crucial but perhaps better to rename the module Qgis->QGIS
Steps to reproduce
Describe as precisely as possible how to reproduce the bug. Try to isolate a minimal number of steps. Also describe reproducibility (always, random ...).
OS, OTB version or tag, information related to build (binaries, superbuild, system libs ...)