build: sort.py: strip trailing whitespace in all lines

Currently the output is mangled if the last item on the line contains
trailing whitespace and is moved when sorting.

So remove trailing whitespace in all lines (that is, not just in lines
containing supported commands).

Leave leading whitespace as is for now since it could potentially be
used for indentation.

Before:

    $ printf '# hello world  \nprivate-bin a,b  \nprivate-bin b,a  \nprivate-bin  a,b\n' \
      >foo.profile
    $ ./contrib/sort.py -n foo.profile | tr ' ' .
    sort.py:.checking.1.profile(s)...
    foo.profile:3:-private-bin.b,a..
    foo.profile:3:+private-bin.a..,b

After:

    $ printf '# hello world  \nprivate-bin a,b  \nprivate-bin b,a  \n' \
      >foo.profile
    $ ./contrib/sort.py -n foo.profile | tr ' ' .
    sort.py:.checking.1.profile(s)...
    foo.profile:1:-#.hello.world..
    foo.profile:1:+#.hello.world
    foo.profile:2:-private-bin.a,b..
    foo.profile:2:+private-bin.a,b
    foo.profile:3:-private-bin.b,a..
    foo.profile:3:+private-bin.a,b

Author: kmk3

contrib/sort.py

@@ -9,7 +9,7 @@
 from sys import argv, exit as sys_exit, stderr
 
 __doc__ = f"""\
-Sort the arguments of commands in profiles.
+Strip whitespace and sort the arguments of commands in profiles.
 
 Usage: {path.basename(argv[0])} [-h] [-i] [-n] [--] [/path/to/profile ...]
 
@@ -20,6 +20,9 @@
 
 Note that this is only applicable to commands that support multiple arguments.
 
+Trailing whitespace is removed in all lines (that is, not just in lines
+containing supported commands).
+
 Options:
     -h  Print this message.
     -i  Edit the profile file(s) in-place (this is the default).
@@ -72,7 +75,7 @@ def check_profile(filename, overwrite):
         was_fixed = False
         fixed_profile = []
         for lineno, original_line in enumerate(lines, 1):
-            line = original_line
+            line = original_line.rstrip()
             if line[:12] in ("private-bin ", "private-etc ", "private-lib "):
                 line = f"{line[:12]}{sort_alphabetical(line[12:])}"
             elif line[:13] in ("seccomp.drop ", "seccomp.keep "):