Fix the Travis configuration

Without this, failed builds of master trigger another "mvn install".

See: https://gist.github.com/ctrueden/ae0f024a0cdf2cb53c915d75b0759553

.travis/build.sh

 #!/bin/sh
 dir="$(dirname "$0")"
-test "$TRAVIS_SECURE_ENV_VARS" = true \
+if [ "$TRAVIS_SECURE_ENV_VARS" = true \
   -a "$TRAVIS_PULL_REQUEST" = false \
-  -a "$TRAVIS_BRANCH" = master &&
-  mvn -Pdeploy-to-imagej deploy --settings "$dir/settings.xml" ||
+  -a "$TRAVIS_BRANCH" = master ]
+then
+  mvn -Pdeploy-to-imagej deploy --settings "$dir/settings.xml"
+else
   mvn install
+fi