Removing gomp for Visual Studio

Linking currently fails in Visual Studio due to a missing library
"gomp.lib". This is not needed in Visual Studio. OpenMP works
without it.

Change-Id: I39e204a8dd4f1b7425df7d4b222d86a8bb961432
diff --git a/internal/ceres/CMakeLists.txt b/internal/ceres/CMakeLists.txt
index 56f6c69..46c9a96 100644
--- a/internal/ceres/CMakeLists.txt
+++ b/internal/ceres/CMakeLists.txt
@@ -151,7 +151,9 @@
 ENDIF (${CXSPARSE_FOUND})
 
 IF (${OPENMP_FOUND})
-  LIST(APPEND CERES_LIBRARY_DEPENDENCIES gomp)
+  IF (NOT MSVC)
+    LIST(APPEND CERES_LIBRARY_DEPENDENCIES gomp)
+  ENDIF (NOT MSVC)
 ENDIF (${OPENMP_FOUND})
 
 IF (${PROTOBUF_FOUND})