btrfs-progs: install Python bindings

btrfs-progs currently builds the Python bindings for libbtrfsutil but doesn't
actually install them. With this patch, the bindings are installed and exposed
as python3Packages.btrfsutil.

pkgs/tools/filesystems/btrfs-progs/default.nix

@@ -38,6 +38,8 @@ stdenv.mkDerivation rec {
 
   makeFlags = lib.optionals stdenv.hostPlatform.isGnu [ "udevruledir=$(out)/lib/udev/rules.d" ];
 
+  installFlags = [ "install_python" ];
+
   enableParallelBuilding = true;
 
   passthru.tests = {

pkgs/top-level/python-packages.nix

@@ -1407,6 +1407,8 @@ in {
 
   btrfs = callPackage ../development/python-modules/btrfs { };
 
+  btrfsutil = toPythonModule (pkgs.btrfs-progs.override { python3 = self.python; });
+
   bugsnag = callPackage ../development/python-modules/bugsnag { };
 
   bugwarrior = callPackage ../development/python-modules/bugwarrior { };