CommandSelLdrTestNacl: Use -a instead of NACL_DANGEROUS_ENABLE_FILE_ACCESS
CommandSelLdrTestNacl: Use -a instead of NACL_DANGEROUS_ENABLE_FILE_ACCESS

The command line args are preferred over the more implicit env vars.
This also makes it easier to copy and paste the command line that
command_tester.py prints.

BUG=http://code.google.com/p/nativeclient/issues/detail?id=862
TEST=run_hello_world_test with --nacl_glibc

Review URL: http://codereview.chromium.org/3550009

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@3398 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client