Fixed old GCC error

src/openpose/core/datum.cpp

@@ -23,7 +23,7 @@ namespace op
         faceRectangles{datum.faceRectangles},
         faceKeypoints{datum.faceKeypoints},
         handRectangles{datum.handRectangles},
-        handKeypoints{datum.handKeypoints},
+        handKeypoints(datum.handKeypoints), // Parentheses instead of braces to avoid error in GCC 4.8
         // Other parameters
         scaleInputToOutput{datum.scaleInputToOutput},
         scaleNetToOutput{datum.scaleNetToOutput},

src/openpose/hand/handExtractor.cpp

@@ -98,7 +98,7 @@ error("Hands extraction is not implemented yet. COMING SOON!", __LINE__, __FUNCT
         catch (const std::exception& e)
         {
             error(e.what(), __LINE__, __FUNCTION__, __FILE__);
-            return std::array<Array<float>, 2>{};
+            return std::array<Array<float>, 2>(); // Parentheses instead of braces to avoid error in GCC 4.8
         }
     }