Replace backticks with repr() or "%r"

From SF patch #852334.
diff --git a/Lib/bsddb/dbtables.py b/Lib/bsddb/dbtables.py
index 6edfd29..e1d2c43 100644
--- a/Lib/bsddb/dbtables.py
+++ b/Lib/bsddb/dbtables.py
@@ -206,7 +206,7 @@
         try:
             key, data = cur.first()
             while 1:
-                print `{key: data}`
+                print repr({key: data})
                 next = cur.next()
                 if next:
                     key, data = next
@@ -341,9 +341,9 @@
         try:
             tcolpickles = self.db.get(_columns_key(table))
         except DBNotFoundError:
-            raise TableDBError, "unknown table: " + `table`
+            raise TableDBError, "unknown table: %r" % (table,)
         if not tcolpickles:
-            raise TableDBError, "unknown table: " + `table`
+            raise TableDBError, "unknown table: %r" % (table,)
         self.__tablecolumns[table] = pickle.loads(tcolpickles)
 
     def __new_rowid(self, table, txn) :
@@ -384,7 +384,7 @@
                 self.__load_column_info(table)
             for column in rowdict.keys() :
                 if not self.__tablecolumns[table].count(column):
-                    raise TableDBError, "unknown column: "+`column`
+                    raise TableDBError, "unknown column: %r" % (column,)
 
             # get a unique row identifier for this row
             txn = self.env.txn_begin()
@@ -535,7 +535,7 @@
             columns = self.tablecolumns[table]
         for column in (columns + conditions.keys()):
             if not self.__tablecolumns[table].count(column):
-                raise TableDBError, "unknown column: "+`column`
+                raise TableDBError, "unknown column: %r" % (column,)
 
         # keyed on rows that match so far, containings dicts keyed on
         # column names containing the data for that row and column.