SqlQuery.execute() and StatementPreparer.execute() have incorrect documentation

[richard-shurtz]

SqlQuery.execute() indicates @return whether the query succeeded in its execution And StatementPrepared.execute() indicates return if the query succeeded or not But the underlying jdbc documentation indicates true if the first result is a ResultSet object; false if it is an update count or there are no results [https://docs.oracle.com/javase/7/docs/api/java/sql/Statement.html#execute(java.lang.String)]

In practice, any INSERT statement executed with .execute() returns false, which the Relate documentation would have you believe indicates that the query failed somehow.

We should update the documentation to match the jdbc documentation