Makefile: change regress find(1) -perm to be more liberal

I typically use umask 077, therefore the -perm of find(1)
must be more liberal to catch executable files.
Repair regress/neubot/bittorrent/config.py
Repair the regress/neubot/http/rootdir.sh test
Preliminary step to repair regress/Makefile tests

I need to prefix neubot to all the files of the core of neubot, to ease
the comparison between the past and what we install now.
Repair the regress/Makefile tests
Merge branch 'repair_regress'