[BUGS] typos in the docu

[Stefan Hans]

http://developer.postgresql.org/docs/postgres/kernel-resources.html 16.5.1 "FreeBSD" ... $ systcl -w kern.ipc.shmall=32768 $ systcl -w kern.ipc.shmmax=134217728 $ systcl -w kern.ipc.semmap=256 "Linux" ... $ systcl -w kernel.shmmax=134217728 $ systcl -w kernel.shmall=2097152 systcl is wrong sysctl not Stefan