Simplify default devConfig.command assignment

[ehmicky]

When dev.command is defined, we override the detected framework's command and args. The way this is currently done can be simplified since the branch checks that devConfig.command is defined. The assignLoudly() function assigns a default value when devConfig.command is not defined, but that can never happen in that branch, so can be removed. Furthermore, the console.log() message is printed in the wrong opposite condition.