bug: crash on NumberFormatException when parsing test

[surli]

Crash with the following error:

Exception in thread "Thread-2" java.lang.NumberFormatException: null
        at java.lang.Integer.parseInt(Integer.java:542)
        at java.lang.Integer.parseInt(Integer.java:615)
        at fr.inria.jtravis.parsers.MavenLogParser.parseTestLine(MavenLogParser.java:52)
        at fr.inria.jtravis.parsers.MavenLogParser.advancedParseLog(MavenLogParser.java:102)
        at fr.inria.jtravis.parsers.MavenLogParser.parseLog(MavenLogParser.java:67)
        at fr.inria.jtravis.parsers.LogParser.getTestsInformation(LogParser.java:113)
        at fr.inria.jtravis.entities.Log.getTestsInformation(Log.java:52)
        at fr.inria.spirals.repairnator.realtime.RTScanner.isRepositoryInteresting(RTScanner.java:261)
        at fr.inria.spirals.repairnator.realtime.InspectJobs.run(InspectJobs.java:47)
        at java.lang.Thread.run(Thread.java:748)

Reported from eclipse-repairnator/repairnator#791