iterator limit now match malloc in protocol listing, fix #21, ref #13

[illwieckz]

Hi, the for test now checks if i < n_server_types, even if Q_UNKNOWN_TYPE is always the last gametype.

• fix the issue iterator limit doesn't match malloc in protocol list code #21, needed by PR Add json support, fix #10, ref XQF/xqf#12  #13 .

This issue is more than 13 years old, but since Q_UNKNOWN_TYPE is always the last gametype, no problem has never occured.

[illwieckz]

This PR can be merged after #32 or before, as you want, but it must be merged before all others.