Fix 2 'except' statements that will bug when moving to Python 3

Previous code relied on the fact that the exception target is kept past
the end of the except clause. 2to3 is not smart enough to detect that.

Without this change, a different OperationalError exception would be
ignored because there's already a local variable of the same name.

neo/lib/logger.py

@@ -124,18 +124,19 @@ class NEOLogger(Logger):
     def commit(self):
         try:
             self._db.commit()
-        except sqlite3.OperationalError, e:
+        except sqlite3.OperationalError as e:
             x = e.args[0]
-            if x == 'database is locked':
-                sys.stderr.write('%s: retrying to emit log...' % x)
-                while e.args[0] == x:
-                    try:
-                        self._db.commit()
-                    except sqlite3.OperationalError, e:
-                        continue
-                    sys.stderr.write(' ok\n')
-                    return
-            raise
+            if x != 'database is locked':
+                raise
+            sys.stderr.write('%s: retrying to emit log...' % x)
+            while 1:
+                try:
+                    self._db.commit()
+                    break
+                except sqlite3.OperationalError as e:
+                    if e.args[0] != x:
+                        raise
+            sys.stderr.write(' ok\n')
 
     def backlog(self, max_size=1<<24, max_packet=None):
         with self:

neo/storage/database/sqlite.py

@@ -42,18 +42,19 @@ def unique_constraint_message(table, *columns):
 def retry_if_locked(f, *args):
     try:
         return f(*args)
-    except sqlite3.OperationalError, e:
+    except sqlite3.OperationalError as e:
         x = e.args[0]
-        if x == 'database is locked':
-            msg = traceback.format_exception_only(type(e), e)
-            msg += traceback.format_stack()
-            logging.warning(''.join(msg))
-            while e.args[0] == x:
-                try:
-                    return f(*args)
-                except sqlite3.OperationalError, e:
-                    pass
-        raise
+        if x != 'database is locked':
+            raise
+        msg = traceback.format_exception_only(type(e), e)
+        msg += traceback.format_stack()
+        logging.warning(''.join(msg))
+        while 1:
+            try:
+                return f(*args)
+            except sqlite3.OperationalError as e:
+                if e.args[0] != x:
+                    raise
 
 
 class SQLiteDatabaseManager(DatabaseManager):