Updated usage of METH_X definitions for python 3.

Python 3 requires METH_VARARGS | METH_KEYWORDS, not just METH_KEYWORDS.

modules/python/src2/cv2.cpp

@@ -1196,7 +1196,7 @@ static PyMethodDef methods[] = {
 
 #include "pyopencv_generated_func_tab.h"
   {"createTrackbar", pycvCreateTrackbar, METH_VARARGS, "createTrackbar(trackbarName, windowName, value, count, onChange) -> None"},
-  {"setMouseCallback", (PyCFunction)pycvSetMouseCallback, METH_KEYWORDS, "setMouseCallback(windowName, onMouse [, param]) -> None"},
+  {"setMouseCallback", (PyCFunction)pycvSetMouseCallback, METH_VARARGS | METH_KEYWORDS, "setMouseCallback(windowName, onMouse [, param]) -> None"},
   {NULL, NULL},
 };
 

modules/python/src2/gen2.py

@@ -543,7 +543,7 @@ class FuncInfo(object):
             p2 = s.rfind(")")
             docstring_list = [s[:p1+1] + "[" + s[p1+1:p2] + "]" + s[p2:]]
 
-        return Template('    {"$py_funcname", (PyCFunction)$wrap_funcname, METH_KEYWORDS, "$py_docstring"},\n'
+        return Template('    {"$py_funcname", (PyCFunction)$wrap_funcname, METH_VARARGS | METH_KEYWORDS, "$py_docstring"},\n'
                         ).substitute(py_funcname = self.variants[0].wname, wrap_funcname=self.get_wrapper_name(),
                                      py_docstring = "  or  ".join(docstring_list))