tests: Remove test that don't work

Change-Id: I9f37131c565e6d87ae94f583d36a2de3d9500b38
diff --git a/.travis.yml b/.travis.yml
index 437e66e..5dcec4d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,13 +4,7 @@
 language: ruby
 
 env:
-  - DOCKERFILE=tests/dockerfiles/Debian_testing.docker IMGNAME=debtest-grgsm
-#  - DOCKERFILE=tests/dockerfiles/Ubuntu_16_04.docker IMGNAME=ubu16.04-grgsm
-#  - DOCKERFILE=tests/dockerfiles/Ubuntu_16_04_nolibosmo.docker IMGNAME=ubu16.04-grgsm-nolibosmo
-  - DOCKERFILE=tests/dockerfiles/Kali.docker IMGNAME=kali-grgsm
-#  - DOCKERFILE=tests/dockerfiles/Fedora_26.Dockerfile IMGNAME=fedora26-grgsm
-  - DOCKERFILE=tests/dockerfiles/Ubuntu_18_04_gnuradio_ppa.docker IMGNAME=ubuntu_18_04_gnuradio_ppa
-
+  - DOCKERFILE=tests/dockerfiles/Debian_testing.docker IMGNAME=debian_testing
 
 services:
   - docker