Two reasons:  First of all, the class that is being tested is really called RemoteIndices
rather than Indices.  Secondly, I want to introduce the static indices from dune-typetree
into dune-common, as decided on the 2015 Dune developer meeting.  They reside in a namespace
Dune::Indices, hence the appropriate name for a unit test would be indicestest.cc.
Unfortunately, cmake does not allow two tests with the same name.