fix for Eclipse p2 bug #28

2 jobs for master in 20 minutes and 18 seconds (queued for 8 seconds)
Name Stage Failure
maven38-java11-sonar Build
1208482 [ERROR] Re-run Maven using the -X switch to enable full debug logging.
1208482 [ERROR]
1208482 [ERROR] For more information about the errors and possible solutions, please read the following articles:
1208483 [ERROR] [Help 1]
1208483 [ERROR]
1208483 [ERROR] After correcting the problems, you can resume the build with the command
1208483 [ERROR] mvn <args> -rf :org.ow2.sat4j.pb
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1