Unset __PYENV_LAUNCHER__ for frameworks.

Fixes #322

Author: pnasrat

virtualenv.py

@@ -1257,6 +1257,10 @@ def install_python(home_dir, lib_dir, inc_dir, bin_dir, site_packages, clear):
     mkdir(bin_dir)
     py_executable = join(bin_dir, os.path.basename(sys.executable))
     if 'Python.framework' in prefix:
+        # OS X framework builds cause validation to break
+        # https://github.com/pypa/virtualenv/issues/322
+        if os.environ.get('__PYVENV_LAUNCHER__'):
+          os.unsetenv('__PYVENV_LAUNCHER__')
         if re.search(r'/Python(?:-32|-64)*$', py_executable):
             # The name of the python executable is not quite what
             # we want, rename it.