Clarified the comment for the ShellExecute function. Added text indicating that the EnvironmentVariables and Status parameters are ignored in a pre-UEFI Shell 2.0 environment and that the Output parameter is ignored in a UEFI Shell 2.0 environment. git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10858 6f19259b-4bc3-4df7-8a09-765794883524