Fix Travis builds (#1459)

* remove manual geckodriver download

* remove env variable

* maybe 0.27 is broken?

.travis.yml

@@ -38,9 +38,12 @@ install:
   - rustup target add wasm32-unknown-unknown
   - cargo +stable install wasm-pack
   - curl --retry 5 -LO https://github.com/mozilla/geckodriver/releases/download/v0.26.0/geckodriver-v0.26.0-linux64.tar.gz
-  - tar -xzf geckodriver-v0.26.0-linux64.tar.gz
+  - mkdir geckodriver
+  - tar -xzf geckodriver-v0.26.0-linux64.tar.gz -C geckodriver
+  - export PATH="$PATH:$PWD/geckodriver"
+  - geckodriver --version
   - ./ci/install_cargo_web.sh
 
 script:
   - ./ci/run_stable_checks.sh
-  - GECKODRIVER="$(pwd)/geckodriver" HTTPBIN_URL="http://localhost:8000" ./ci/run_tests.sh
+  - HTTPBIN_URL="http://localhost:8000" ./ci/run_tests.sh