title: Do we need to define spring.profile.active in yml if declaring user defined environment variable in PCF?
body: <p>On Pivotal Cloud Foundry, say I define this user defined environment variable as SPRING_PROFILE_ACTIVE with value say DEV, then do I need to define in bootstrap.yml, SPRING.PROFILE.ACTIVE (but in the yml way) and define the profile name?</p>
  
  <p>Also is this a reserved environment variable? I was not able to find it in PCF docs.</p>
  
  <p>I was thinking of an approach of defining a random user defined variable name on PCF (say ACTIVE_PROFILE) and then in my bootstrap.yml refer to it as spring.profiles.active = ${ACTIVE_PROFILE: local} where I have flexibility to mention the default. Want to understand what is the difference between two approach?</p>