travis: load cache, but dump it - just testing!

.travis.yml

@@ -36,6 +36,10 @@ before_script:
   - cargo fmt --all -- --check
 
 script:
+  # dump the cache
+  - cargo clean
+  - rm -fr ~/.cargo/git
+  - rm -fr ~/.cargo/registry
   # we set release as build type for all steps to benefit from already compiled packages in prior steps
   - cargo +nightly clippy --release --target=${TARGET} -- -D warnings
   - cargo +nightly test --release --verbose --all --target=${TARGET}