synth not removed from synths[] on failure

[Okash Khawaja]

Hi,

In synth.c synths[] array caches currently loaded synths. It is checked
when adding new synths. The synth_add function adds new synth to
synths[] before taking into account the result of do_synth_init. So if
do_synth_init fails, the failed synth remains cached in synths[]. Next
time user loads same synth which failed last time, it will succeed.

Adding the synth after do_synth_init succeeds seems like right solution
to me. Let me know if I have missed something here. Will be sending a
patch later.

Thanks,
Okash