include enumeration of missing permissions in error log

[kurahaupo]

put extra info in log to help diagnose #1008

[kurahaupo]

The travis-ci failure is because com.android.billingclient:billing has been updated.

> Lint found errors in the project; aborting build.
  
  Fix the issues identified by lint, or add the following to your build script to proceed with errors:
  ...
  android {
      lintOptions {
          abortOnError false
      }
  }
  ...
  
  Errors found:
  
  /home/travis/build/jberkel/sms-backup-plus/app/build.gradle:58: Error:
 A newer version of com.android.billingclient:billing than 2.0.3 is available: 2.1.0 [GradleDependency]
      implementation 'com.android.billingclient:billing:2.0.3'
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  

[kurahaupo]

@jberkel I'm loath to push any patch where the CI fails, even though that appears to be unrelated to the patch. Your advice would be much appreciated.