there might b e a better solution that this now... this is kind of old school but it should work...
first, a little background: look in /etc/rc.d/. you will see an rc#.d that corresponds to all 7 runlevels (0-6). in another directory called init.d contains that actual start/stop scripts for each daemon. inside each of the rc#.d dirs are symlinks that refer back to init.d. these symlinks control what is started with each runlevel and in which order. so basically when you use chkconfig it is managing these symlinks for you.
anyway, when you go into, lets say, rc5.d, you will see everything that is going to start in runlevel 5. each symlink will have a number and letter code next to it that determines its position within the directory which is what controls the order in which they start. so theoretically if you were to mrename the snort symlink to a letter/number code to appear before mysql you would stop getting that error.
a few warnings:
1) i have no idea what will happen the next time you run chkconfig. it will probably put it back to normal.
2) you could possibly render your system non-bootable. highly unlikely, but possible.
3) the two you would want to modify are for runlevel 3 and 5. reason: it starts rl3 first so when rl5 init's i think it will already see that mysql and snort are running so it does not try to start them again so if rc3.d is not modified the startup order for daemons in both 3 and 5 will not be either. (i could be wrong on that one though)
4) the mysql daemon (in my experience) takes longer than most another daemons i've seen to start so it could be that mysql is actually being initiated first but not fully loading until sometime after snort attempts to start.
5) changing the start order can break things if you move something that now is told to start before something that it is dependent on.
if #4 turns out to be true, where mysql is actually loading first just not getting done in time one possible workaround is to use chkconfig to tell mysql to run in 3 and 5 but tell snort to only start in 5. that way by the time linux issues init 5 mysql is already running - before snort is initiated.
hopefully someone has a better answer for you