debian: stop using dh_python2 ${python:Depends}
When dh_python2 parses the requires.txt files in Calamari and
Calamari's bundled libraries, it translates the dependencies listed
there into "python-" packages and adds them into ${python:Depends}.
In the past this has led to the calamari-server .deb depending on system packages that do not exist, which leads to installation failures.
Since ${python:Depends} doesn't work well with Calamari's method of bundling libraries in a virtualenv, just remove it and hard-code the list of python Depends in /debian/control.
(I've just copied & pasted the existing list that dh_python2 was already picking up, so maybe this Depends list could be trimmed further, with experimentation.)
(cherry picked from commit a47b3ffb75b319591caa631f7bfca1424bcd4818)
Conflicts:
debian/control
Resolved by using the list from dpkg -I from the current build on
this branch.
(FYI I've cherry-picked this to the downstream packaging branch already; this is just to get it upstreamed too.)