gapi: fix build with GCC 4.8

modules/gapi/src/backends/fluid/gfluidbuffer.cpp

@@ -347,12 +347,20 @@ std::unique_ptr<fluid::BufferStorage> createStorage(int capacity, int desc_width
         std::unique_ptr<fluid::BufferStorageWithBorder> storage(new BufferStorageWithBorder);
         storage->init(type, border_size, border.value());
         storage->create(capacity, desc_width, type);
+#if defined __GNUC__ && __GNUC__ < 5
+        return std::move(storage);
+#else
         return storage;
+#endif
     }
 
     std::unique_ptr<BufferStorageWithoutBorder> storage(new BufferStorageWithoutBorder);
     storage->create(capacity, desc_width, type);
+#if defined __GNUC__ && __GNUC__ < 5
+    return std::move(storage);
+#else
     return storage;
+#endif
 }
 
 std::unique_ptr<BufferStorage> createStorage(const cv::gapi::own::Mat& data, cv::gapi::own::Rect roi);
@@ -360,7 +368,11 @@ std::unique_ptr<BufferStorage> createStorage(const cv::gapi::own::Mat& data, cv:
 {
     std::unique_ptr<BufferStorageWithoutBorder> storage(new BufferStorageWithoutBorder);
     storage->attach(data, roi);
+#if defined __GNUC__ && __GNUC__ < 5
+    return std::move(storage);
+#else
     return storage;
+#endif
 }
 } // namespace
 } // namespace fluid