This adds a function (from DxeMain.c) that calculates and sets a CRC into a system table header and then calls the function in the 2 places where the shell changes the system table.
signed-off-by: jcarsey
reviewed-by: geekboy15a
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12536 6f19259b-4bc3-4df7-8a09-765794883524