Fix documentation for sslcert / sslkey
Fix documentation for sslcert / sslkey

All of the parameters are optional, so there's no need to mention it
separately for these two.

amaniak/pq,everalbum/pq,johto/pq,calebthompson/pq,ScriptRock/pq,flynn/pq,bugreplaydev/pq,jnewmano/pq,bugreplaydev/pq,erichnascimento/pq,lib/pq,StabbyCutyou/pq,VividCortex/pq,cbandy/go-pq,ympons/pq,dongzerun/pq,springning/pq,henrylee2cn/pq,sammi/pq,stvp/pq,jnewmano/pq,beni55/pq,ympons/pq