bug in rez-build --bs option

[nerdvegas]

In src/rezplugins/build_system/cmake.py:

@@ -75,8 +75,8 @@ def bind_cli(cls, parser):
type=str, choices=cls.build_targets,
default=settings.build_target,
help="set the build target (default: %(default)s).")

•    parser.add_argument("--bs", "--build-system", dest="build_system",
  

•                        type=str, choices=cls.build_systems.keys(),
  

•    parser.add_argument("--bs", "--cmake-build-system",
  

this needs
dest="cmake_build_system",

If not when running with --bs it won't be picked in line 96