common-process-args does not allow arguments in STARTUP variable

["Marco Clocchiatti" <ziapannocchia@gmail.com>]

in /etc/X11/Xsession.d/20x11-common_process-args
at line 36:
	        STARTUP_FULL_PATH=$(/usr/bin/which "$1" || true)

please change $1 with $0, because startup function does not allows arguments.
for example, a konq.desktop such the following fails:

cloc3@unix-client:/etc/X11/Xsession.d$ cat /usr/share/xsessions/konq.desktop
[Desktop Entry]
Encoding=UTF-8
# The names/descriptions should really be better
Name=Internet_konqueror
Name[it]=Internet_konqueror
Comment=seleziona questa etichetta per navigare con konqueror
Comment[en]=click here to browsing with konqueror
Exec=/usr/bin/konqueror --geometry 1280x1024+0+0
Icon=
Type=Application