base

change return type from void to int on execSQL() methods

1. let execSQL() methods return the number of rows affected by the SQL
staement executed.
2. remove synchronized on 2 public methods. since public API is not
supposed to have synchronized, this was a mistake in previously submitted
CL

Change-Id: Ic610a0c38e7bd7c77006a08c7b82fa01957739e5