Style improvements in gdb/python

This fixes a few minor style issues I found in gdb/python: some
unnecessary casts, the removal of an unnecessary local variable, and
one instance of incorrect formatting.

Tested by rebuilding and re-running gdb.python.

gdb/ChangeLog
2019-01-02  Tom Tromey  <tom@tromey.com>

	* python/py-inferior.c (gdbpy_initialize_inferior): Fix
	indentation.
	* python/py-frame.c (frapy_older): Remove cast.
	(frapy_newer): Likewise.
	* python/py-breakpoint.c (local_setattro): Remove cast.
	* python/py-arch.c (archpy_name): Remove local variable.
	* python/py-type.c (gdbpy_lookup_type): Remove cast.

gdb/python/py-arch.c

@@ -97,14 +97,11 @@ archpy_name (PyObject *self, PyObject *args)
 {
   struct gdbarch *gdbarch = NULL;
   const char *name;
-  PyObject *py_name;
 
   ARCHPY_REQUIRE_VALID (self, gdbarch);
 
   name = (gdbarch_bfd_arch_info (gdbarch))->printable_name;
-  py_name = PyString_FromString (name);
-
-  return py_name;
+  return PyString_FromString (name);
 }
 
 /* Implementation of

gdb/python/py-breakpoint.c

@@ -1196,7 +1196,7 @@ local_setattro (PyObject *self, PyObject *name, PyObject *v)
 	}
     }
 
-  return PyObject_GenericSetAttr ((PyObject *)self, name, v);
+  return PyObject_GenericSetAttr (self, name, v);
 }
 
 static gdb_PyGetSetDef breakpoint_object_getset[] = {

gdb/python/py-frame.c

@@ -416,7 +416,7 @@ frapy_older (PyObject *self, PyObject *args)
   END_CATCH
 
   if (prev)
-    prev_obj = (PyObject *) frame_info_to_frame_object (prev);
+    prev_obj = frame_info_to_frame_object (prev);
   else
     {
       Py_INCREF (Py_None);
@@ -449,7 +449,7 @@ frapy_newer (PyObject *self, PyObject *args)
   END_CATCH
 
   if (next)
-    next_obj = (PyObject *) frame_info_to_frame_object (next);
+    next_obj = frame_info_to_frame_object (next);
   else
     {
       Py_INCREF (Py_None);

gdb/python/py-inferior.c

@@ -958,8 +958,8 @@ gdbpy_initialize_inferior (void)
   if (PyType_Ready (&membuf_object_type) < 0)
     return -1;
 
-  return gdb_pymodule_addobject (gdb_module, "Membuf", (PyObject *)
-				 &membuf_object_type);
+  return gdb_pymodule_addobject (gdb_module, "Membuf",
+				 (PyObject *) &membuf_object_type);
 }
 
 static gdb_PyGetSetDef inferior_object_getset[] =

gdb/python/py-type.c

@@ -1402,7 +1402,7 @@ gdbpy_lookup_type (PyObject *self, PyObject *args, PyObject *kw)
   if (! type)
     return NULL;
 
-  return (PyObject *) type_to_type_object (type);
+  return type_to_type_object (type);
 }
 
 int