Remove TestWithExternalIndex test suite

Change-Id: Ifaff4f41a373f658b433406e2e6a30d09813dd91
diff --git a/.gitignore b/.gitignore
index a89d9ae..cf2be21 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,4 +25,5 @@
 /dependency-reduced-pom.xml
 /bin
 /src/test/resources/sample-index
+/src/test/java/de/ids_mannheim/korap/collection/TestWithExternalIndex.java
 /krill_cache/