Remove RAFT specialization. (#3727)

This PR removes a deprecation warning coming from RAFT. Including the specializations header no longer has an effect, so it can be safely removed.

Authors:
  - Bradley Dice (https://github.com/bdice)

Approvers:
  - Chuck Hastings (https://github.com/ChuckHastings)

URL: #3727

Author: bdice

cpp/src/community/legacy/spectral_clustering.cu

@@ -24,9 +24,6 @@
 #include <cugraph/legacy/graph.hpp>
 #include <cugraph/utilities/error.hpp>
 
-#if defined RAFT_COMPILED
-#include <raft/distance/specializations.cuh>
-#endif
 #include <raft/spectral/modularity_maximization.cuh>
 #include <raft/spectral/partition.cuh>