Ignore compile module-info class-files

Now that they are not checked in any more.

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1906324 13f79535-47bb-0310-9956-ffa450edef68

.gitignore

@@ -37,3 +37,6 @@ TEST-org.apache.poi*.xml
 /*/build/
 dist
 lib/
+
+# Compiled module-info class-files
+/poi*/src/*/java9/*.class