java.lang.IllegalStateException: value is absent.

[siom79]

Issue introduced through PR:

java.lang.IllegalStateException: value is absent.
	at japicmp.util.Optional$Absent.get(Optional.java:70)
	at japicmp.compat.CompatibilityChanges$4.callback(CompatibilityChanges.java:391)
	at japicmp.compat.CompatibilityChanges$4.callback(CompatibilityChanges.java:385)
	at japicmp.compat.CompatibilityChanges.forAllSuperclasses(CompatibilityChanges.java:209)
	at japicmp.compat.CompatibilityChanges.checkIfMethodsHaveChangedIncompatible(CompatibilityChanges.java:385)
	at japicmp.compat.CompatibilityChanges.evaluateBinaryCompatibility(CompatibilityChanges.java:59)
	at japicmp.compat.CompatibilityChanges.evaluate(CompatibilityChanges.java:28)
	at japicmp.cmp.JarArchiveComparator.checkBinaryCompatibility(JarArchiveComparator.java:178)
	at japicmp.cmp.JarArchiveComparator.compareClassLists(JarArchiveComparator.java:214)
	at japicmp.cmp.JarArchiveComparator.createAndCompareClassLists(JarArchiveComparator.java:187)
	at japicmp.cmp.JarArchiveComparator.compare(JarArchiveComparator.java:97)
	at japicmp.cli.JApiCli.run(JApiCli.java:31)
	at japicmp.JApiCmp.main(JApiCmp.java:35)