Disable collision-protect in parallel_emerge.

parallel_emerge

 #!/usr/bin/python2.6
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Program to run emerge in parallel, for significant speedup.
 
 Usage:
  ./parallel_emerge [--board=BOARD] [--workon=PKGS] [--no-workon-deps]
                    [emerge args] package"
@@ skipping 338 matching lines @@
       opts.setdefault("--resume", True)
     if "--buildpkgonly" in opts:
       # --buildpkgonly will not merge anything, so it overrides all binary
       # package options.
       for opt in ("--getbinpkg", "--getbinpkgonly",
                   "--usepkg", "--usepkgonly"):
         opts.pop(opt, None)
     if (settings.get("PORTAGE_DEBUG", "") == "1" and
         "python-trace" in settings.features):
       portage.debug.set_trace(True)
+    # Since we don't have locking around merges, the collision-protect
+    # feature doesn't make sense.
+    settings.features.discard("collision-protect")
 
     # Complain about unsupported options
     for opt in ("--ask", "--ask-enter-invalid", "--complete-graph",
                 "--resume", "--skipfirst"):
       if opt in opts:
         print "%s is not supported by parallel_emerge" % opt
         sys.exit(1)
 
     # Make emerge specific adjustments to the config (e.g. colors!)
     adjust_configs(opts, trees)
@@ skipping 899 matching lines @@
       for db_pkg in final_db.match_pkgs(pkg):
         print "Adding %s to world" % db_pkg.cp
         new_world_pkgs.append(db_pkg.cp)
     if new_world_pkgs:
       world_set.update(new_world_pkgs)
 
   print "Done"
 
 if __name__ == "__main__":
   main()