Purge unused variables (to silence warnings)

Change-Id: Ifc11c4bc4725f4c70d6be75208b6906d163754b4

runtime/hsa-runtime/core/runtime/amd_gpu_agent.cpp

@@ -653,10 +653,6 @@ hsa_status_t GpuAgent::EnableDmaProfiling(bool enable) {
 
 hsa_status_t GpuAgent::GetInfo(hsa_agent_info_t attribute, void* value) const {
   const size_t kNameSize = 64;  // agent, and vendor name size limit
-
-  const core::ExtensionEntryPoints& extensions =
-      core::Runtime::runtime_singleton_->extensions_;
-
   const size_t attribute_u = static_cast<size_t>(attribute);
   switch (attribute_u) {
     case HSA_AGENT_INFO_NAME:

runtime/hsa-runtime/core/runtime/hsa_ext_interface.cpp

@@ -264,7 +264,6 @@ bool ExtensionEntryPoints::LoadImage(std::string library_name) {
   void* ptr;
 
   ptr = os::GetExportAddress(lib, "hsa_ext_image_get_capability_impl");
-  bool libIsImage = (ptr != NULL);
   if (ptr != NULL) {
     assert(image_api.hsa_ext_image_get_capability_fn ==
                (decltype(::hsa_ext_image_get_capability)*)hsa_ext_null &&