Replace boost logging with simple logger

!referencetests:214319

* Reduces arm nn binary size ~15%
* Also fixed test logging black hole issues

Change-Id: Iba27db304d9a8088fa46aeb0b52225d93bb56bc8
Signed-off-by: Derek Lamberti <derek.lamberti@arm.com>
diff --git a/src/backends/cl/ClBackendContext.cpp b/src/backends/cl/ClBackendContext.cpp
index 48682b9..a82391c 100644
--- a/src/backends/cl/ClBackendContext.cpp
+++ b/src/backends/cl/ClBackendContext.cpp
@@ -4,14 +4,15 @@
 //
 
 #include "ClBackendContext.hpp"
+
+#include <armnn/Logging.hpp>
+
 #include "ClContextControl.hpp"
 
 #include <arm_compute/core/CL/OpenCL.h>
 #include <arm_compute/core/CL/CLKernelLibrary.h>
 #include <arm_compute/runtime/CL/CLScheduler.h>
 
-#include <boost/log/trivial.hpp>
-
 namespace armnn
 {
 
@@ -34,8 +35,8 @@
             }
             catch (const cl::Error&)
             {
-                BOOST_LOG_TRIVIAL(warning) << "WARNING: Runtime::UnloadNetwork(): an error occurred while waiting for "
-                                              "the queued CL requests to finish";
+                ARMNN_LOG(warning) << "Runtime::UnloadNetwork(): an error occurred while waiting for "
+                                      "the queued CL requests to finish";
                 return false;
             }
         }