Updated travis config : install ghostscript, required for Html2Image

.travis.yml

@@ -10,10 +10,10 @@ jdk:
 # only `sudo: true` allows running tests on Travis CI container infrastructure for faster builds, but testing installation of .deb makes sense
 sudo: true
 
-# Installing ghostcript (optional imagemagick dependency) is required for Html2ImageTest to run
+# Installing ghostscript (optional imagemagick dependency) is required for Html2ImageTest to run
 before_install:
   - sudo apt-get -qq update
-  - sudo apt-get install -y ghostcript
+  - sudo apt-get install -y ghostscript
 
 install:
 - cd libbuild && MAVEN_OPTS="-Xmx6g -Xms2g" mvn clean install && cd ..