wiredTigerEngineRuntimeConfigSetting parameter is deprecated，should be wiredTigerEngineRuntimeConfig

https://docs.mongodb.com/manual/reference/command/setParameter/

wiredTigerEngineRuntimeConfigSetting is not correct in 3.2, should be wiredTigerEngineRuntimeConfig, users cannot figure this out except reading the source code.

An example is also needed to helper MonogDB users:

db.runCommand({ setParameter : 1, "wiredTigerEngineRuntimeConfig" : "cache_size=3G" })