fix Collada: wrong usage of pointer and hidden redeclaration

* Suspicious usage of pointer:

  short *type = 0; // this creates a null pointer

When this is later used for anything then blender would crash.
After following the code and check what happens i strongly believe
the author wanted to use a short and not a pointer to a short here.

* local variable where reused later in same function
While this did no harm, i still felt it was better to use a different
name here to make things more separated:

- moved variable declaraiotns into loop (for int a=0; ...)
- renamed uv_images to uv_image_set
- renamed index variable from i to j in inner loop that
  reused same index name from outer loop

source/blender/collada/DocumentImporter.cpp

@@ -474,9 +474,9 @@ void DocumentImporter::create_constraints(ExtraTags *et, Object *ob)
 {
 	if (et && et->isProfile("blender")) {
 		std::string name;
-		short* type = 0;
-		et->setData("type", type);
-		BKE_constraint_add_for_object(ob, "Test_con", *type);
+		short type = 0;
+		et->setData("type", &type);
+		BKE_constraint_add_for_object(ob, "Test_con", type);
 		
 	}
 }
@@ -587,8 +587,8 @@ std::vector<Object *> *DocumentImporter::write_node(COLLADAFW::Node *node, COLLA
 			++lamp_done;
 		}
 		while (controller_done < controller.getCount()) {
-			COLLADAFW::InstanceGeometry *geom = (COLLADAFW::InstanceGeometry *)controller[controller_done];
-			ob = mesh_importer.create_mesh_object(node, geom, true, uid_material_map, material_texture_mapping_map);
+			COLLADAFW::InstanceGeometry *geometry = (COLLADAFW::InstanceGeometry *)controller[controller_done];
+			ob = mesh_importer.create_mesh_object(node, geometry, true, uid_material_map, material_texture_mapping_map);
 			if (ob == NULL) {
 				report_unknown_reference(*node, "instance_controller");
 			}

source/blender/collada/GeometryExporter.cpp

@@ -149,8 +149,8 @@ void GeometryExporter::operator()(Object *ob)
 		}
 		else {
 			bool all_uv_layers = !this->export_settings->active_uv_only;
-			std::set<Image *> uv_images = bc_getUVImages(ob, all_uv_layers);
-			createPolylists(uv_images, has_uvs, has_color, ob, me, geom_id, norind);
+			std::set<Image *> uv_image_set = bc_getUVImages(ob, all_uv_layers);
+			createPolylists(uv_image_set, has_uvs, has_color, ob, me, geom_id, norind);
 		}
 	}
 	

source/blender/collada/ImageExporter.cpp

@@ -203,8 +203,8 @@ bool ImagesExporter::hasImages(Scene *sce)
 	
 	for (node = this->export_settings->export_set; node; node = node->next) {
 		Object *ob = (Object *)node->link;
-		int a;
-		for (a = 0; a < ob->totcol; a++) {
+
+		for (int a = 0; a < ob->totcol; a++) {
 			Material *ma = give_current_material(ob, a + 1);
 
 			// no material, but check all of the slots

source/blender/collada/MeshImporter.cpp

@@ -552,7 +552,7 @@ void MeshImporter::mesh_add_edges(Mesh *mesh, int len)
 {
 	CustomData edata;
 	MEdge *medge;
-	int i, totedge;
+	int totedge;
 
 	if (len == 0)
 		return;
@@ -572,7 +572,7 @@ void MeshImporter::mesh_add_edges(Mesh *mesh, int len)
 
 	/* set default flags */
 	medge = &mesh->medge[mesh->totedge];
-	for (i = 0; i < len; i++, medge++)
+	for (int i = 0; i < len; i++, medge++)
 		medge->flag = ME_EDGEDRAW | ME_EDGERENDER | SELECT;
 
 	mesh->totedge = totedge;
@@ -606,12 +606,12 @@ void MeshImporter::read_lines(COLLADAFW::Mesh *mesh, Mesh *me)
 				unsigned int edge_count  = mp->getFaceCount();
 				unsigned int *indices    = mp->getPositionIndices().getData();
 				
-				for (int i = 0; i < edge_count; i++, med++) {
+				for (int j = 0; j < edge_count; j++, med++) {
 					med->bweight = 0;
 					med->crease  = 0;
 					med->flag   |= ME_LOOSEEDGE;
-					med->v1      = indices[2 * i];
-					med->v2      = indices[2 * i + 1];
+					med->v1      = indices[2 * j];
+					med->v2      = indices[2 * j + 1];
 				}
 			}
 		}