Propagating OperationContext mostly compiles:

1. exec/SConscript: temp removed r2common, r2near and s2near
Greg says the r2* is going away, so can probably plug in
OperationContextNoop where needed.

2. this version has modifications to ExtentManager that are
not called and cause compilation errors.  We need some MUCC
for ExtentManager and NamespaceDetails, but LockManager may
be too heavy.  Current thinking is to get this working on the
old EM/NSD APIs.