ogre: Do not assume that ogre plugins have lib prefix on macOS (gazeb…

…osim#454)

Signed-off-by: Silvio <silvio@traversaro.it>
Signed-off-by: William Lew <WilliamMilesLew@gmail.com>

ogre/src/OgreRenderEngine.cc

@@ -425,20 +425,17 @@ void OgreRenderEngine::LoadPlugins()
     std::vector<std::string>::iterator piter;
 
 #ifdef __APPLE__
-    std::string prefix = "lib";
     std::string extension = ".dylib";
 #elif _WIN32
-    std::string prefix = "";
     std::string extension = ".dll";
 #else
-    std::string prefix = "";
     std::string extension = ".so";
 #endif
 
-    plugins.push_back(path+"/"+prefix+"RenderSystem_GL");
-    plugins.push_back(path+"/"+prefix+"Plugin_ParticleFX");
-    plugins.push_back(path+"/"+prefix+"Plugin_BSPSceneManager");
-    plugins.push_back(path+"/"+prefix+"Plugin_OctreeSceneManager");
+    plugins.push_back(path+"/RenderSystem_GL");
+    plugins.push_back(path+"/Plugin_ParticleFX");
+    plugins.push_back(path+"/Plugin_BSPSceneManager");
+    plugins.push_back(path+"/Plugin_OctreeSceneManager");
 
 #ifdef HAVE_OCULUS
     plugins.push_back(path+"/Plugin_CgProgramManager");