fix java 9 build on travis by skipping coveralls
coverall version 4.3.0 does not work with java 9, see
@@ -425,6 +425,8 @@ jar, tar, zip, dump, 7z, arj.
<maven.compiler.release>9</maven.compiler.release>
<commons.jacoco.version>0.7.9</commons.jacoco.version>
<animal.sniffer.skip>true</animal.sniffer.skip>
+ <!-- coverall version 4.3.0 does not work with java 9, see https://github.com/trautonen/coveralls-maven-plugin/issues/112 -->
+ <coveralls.skip>true</coveralls.skip>
</properties>
</profile>
