Drop LD_PRELOAD from shebang, because env doesn't support -S on…

… CloudLinux 7

BUCK

@@ -7,10 +7,7 @@ include_defs('//product.defs.py')
 python_binary(
     name = 'cloudlinux7to8.pex',
     platform = 'py3',
-    # libgcc_s.so.1 is preloaded to workaround crash due to "libgcc_s.so.1 must
-    # be installed for pthread_cancel to work" instead of clean exit after
-    # dist-upgrade, see https://bugs.python.org/issue44434
-    build_args = ['--python-shebang', '/usr/bin/env -S LD_PRELOAD=libgcc_s.so.1 python3'],
+    build_args = ['--python-shebang', '/usr/bin/env python3'],
     main_module = 'cloudlinux7to8.main',
     deps = [
         'dist-upgrader//pleskdistup:lib',