limit on vfs.fs.size - solaris/opensolaris fix

[slash5k1]

I posted the changes i made to "ZABBIX Troubleshooting and Problems" but i would like it to be reviewed and part of the next build.

http://www.zabbix.com/forum/showthread.php?t=13634

*note in the above post I have applied my change to every file in zabbix, when I have only identified this as problem for solaris so only that code should be touched.

cheers

Chris