When using parentheses around parameter values such as MAVEN_OPTS causes exception

[xyloman]

When using parentheses around parameter values such as MAVEN_OPTS causes exception where the maven wrapper is unable to find the main class. Example:

maven-params: &maven-params
  MAVEN_OPTS: ((maven.build.opts))
  MAVEN_CONFIG: ((maven.build.config))
  MAVEN_REPO_MIRROR: ((maven.mirror.url))
  MAVEN_REPO_USERNAME: ((maven.mirror.username))
  MAVEN_REPO_PASSWORD: ((maven.mirror.password))
  MAVEN_REPO_CACHE_ENABLE: true

And then then param.yml does not provide a value for maven.build.ops or provides the following:

maven:
  build:
    ops: 

Will result in the value null being passed to the MAVEN_OPTS instead of "" which results in an error when ever the ./mvnw command is executed in a task. For now we have modified to this syntax:

maven:
  build:
    ops: ""

which appears to work around the issue.