Deleting the generated 'launchpad.config' file is a bad idea because in
contrast to most base platforms, on Linux, we merely create symlinks
from the 'var/run/demo/' directory to the 'bin/' directory instead of
copying the files.
This patch updates the launchpad config to use XML attributes and
removes the built-in default configuration (which is only meaningful
for demo.run anyway).
The memory allocation heuristics in the usb driver provided by dde_linux
changed with the recent commit 71b2b42936.
Apparently, the new variant requires a larger memory pool. Increasing
the quota is a temporary fix until the memory allocator gets revisited.
