Revert "fj-mkdeb.py: run distclean before ./configure"

This reverts commit b4d0b24.

This amends commit 56b86f8 ("Revert "Makefile.in: stop running
distclean on dist"", 2022-06-08) / PR #5182.  Since the revert, `make
dist` itself already runs `make distclean`.

This also means that it is no longer necessary to run ./configure (to
generate "Makefile" from "Makefile.in") before running
./contrib/fj-mkdeb.py.

Misc: This is not a clean revert.

Relates to #5154.

contrib/fj-mkdeb.py

@@ -22,11 +22,6 @@ def run(srcdir, args):
             # prefix should ALWAYS be /usr here.  Discard user-set values
             args.remove(a)
 
-    # Remove generated files.
-    distclean = subprocess.call(['make', 'distclean'])
-    if distclean != 0:
-        return distclean
-
     # Run configure to generate mkdeb.sh.
     first_config = subprocess.call(['./configure', '--prefix=/usr'] + args)
     if first_config != 0: