Sync patches r14315 and r14323 from main trunk.
1. Update dual network stack drivers to produce multiple Driver Binding Protocol. 
2. Fix memory overflow & VariableSize check issue for SetVariable append write.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/branches/UDK2010.SR1@14327 6f19259b-4bc3-4df7-8a09-765794883524