MAX_IQ_THREADS_PER_CONNECTION minimum value changed [CR 395718]

As of 12.6 ESD #5, the minimum value of the MAX_IQ_THREADS_PER_CONNECTION database option is now 3, rather than 2. This value is documented in Chapter 2 “Database Options” in Table 2-1 “General database options” and in “MAX_IQ_THREADS_PER_CONNECTION option” in the section “Alphabetical list of options” in the Sybase IQ Reference Manual.