Fixed memory leaks

Repository_read would not free the odb object after using it.
Object_read_raw didn't close the odb object after usage

pygit2.c

@@ -324,11 +324,14 @@ Repository_read(Repository *self, PyObject *py_hex) {
     if (err < 0)
         return Error_set_py_obj(err, py_hex);
 
-    return Py_BuildValue(
+    PyObject* tuple = Py_BuildValue(
         "(ns#)",
         git_odb_object_type(obj),
         git_odb_object_data(obj),
         git_odb_object_size(obj));
+
+    git_odb_object_close(obj);
+    return tuple;
 }
 
 static PyObject *
@@ -797,6 +800,8 @@ Object_read_raw(Object *self) {
         git_odb_object_data(obj),
         git_odb_object_size(obj));
 
+    git_odb_object_close(obj);
+
 cleanup:
     Py_XDECREF(py_sha);
     return result;