Remove useless variable initialization

Don't initialize variables which are not used before they are assigned.
diff --git a/Objects/abstract.c b/Objects/abstract.c
index d3b9ec0..8892e3e 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2614,8 +2614,7 @@
 PyObject_CallMethod(PyObject *obj, const char *name, const char *format, ...)
 {
     va_list va;
-    PyObject *callable = NULL;
-    PyObject *retval = NULL;
+    PyObject *callable, *retval;
 
     if (obj == NULL || name == NULL) {
         return null_error();
@@ -2638,8 +2637,7 @@
                        const char *format, ...)
 {
     va_list va;
-    PyObject *callable = NULL;
-    PyObject *retval = NULL;
+    PyObject *callable, *retval;
 
     if (obj == NULL || name == NULL) {
         return null_error();
@@ -2662,8 +2660,7 @@
                            const char *format, ...)
 {
     va_list va;
-    PyObject *callable = NULL;
-    PyObject *retval;
+    PyObject *callable, *retval;
 
     if (obj == NULL || name == NULL) {
         return null_error();
@@ -2686,8 +2683,7 @@
                              const char *format, ...)
 {
     va_list va;
-    PyObject *callable = NULL;
-    PyObject *retval;
+    PyObject *callable, *retval;
 
     if (obj == NULL || name == NULL) {
         return null_error();
@@ -3112,7 +3108,8 @@
 PyObject_GetIter(PyObject *o)
 {
     PyTypeObject *t = o->ob_type;
-    getiterfunc f = NULL;
+    getiterfunc f;
+
     f = t->tp_iter;
     if (f == NULL) {
         if (PySequence_Check(o))