Remove IVT from System.ServiceModel on MonoDroid, MonoTouch profiles.

Remove IVT from System.ServiceModel on MonoDroid, MonoTouch profiles.

This is ~identical to commit a3ba2ab7a091b96c9e8917aab9bd9ad042a5d639,
just applied to the MonoDroid and MonoTouch profiles.

Furthermore, without this patch the MonoDroid & MonoTouch profiles fail to
build, as current versions of mcs (nicely) attempt to verify that the output
assembly name matches the IVT of a referenced assembly, which isn't possible
when System.Xml.dll has an IVT entry for System.ServiceModel.Web.dll which
differs from System.ServiceModel.dll's IVT entry for
System.ServiceModel.Web.dll.