don't quote bool for cql

quoted bool is optional in table option DDL, and disallowed in CQL DML

PYTHON-596

cassandra/encoder.py

@@ -40,8 +40,7 @@ def cql_quote(term):
     # The ordering of this method is important for the result of this method to
     # be a native str type (for both Python 2 and 3)
 
-    # Handle quoting of native str and bool types
-    if isinstance(term, (str, bool)):
+    if isinstance(term, str):
         return "'%s'" % str(term).replace("'", "''")
     # This branch of the if statement will only be used by Python 2 to catch
     # unicode strings, text_type is used to prevent type errors with Python 3.