Update debian subdirectory for 6.2.0.

Update debian/copyright for pymdht.
Update debian/control for python2.
Update debian/rules for git repo.
Update debian/watch for watching the snapshot version.
Update debian/tribler.install to install the conf file.
Update debian/clean for using scons.
Remove unnecessary debian/patches.

Signed-off-by: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>