Debugger: More QRegion dumper fixes

Change-Id: I01aaba021fd4893fb521251c9b4b9572c2beef44
Reviewed-by: hjk <hjk121@nokiamail.com>
QNX: Fix broken environment

On systems where QNX_HOST (et al.) are already set by the QNX SDP
installer, just appending to QNX_HOST collides with finding the
Connect.jar package when connecting to a device.

Change-Id: I5d3547396384fe5b421c4b601b52476a23cdfa89
Reviewed-by: Mehdi Fekari <mfekari@blackberry.com>
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>