travis: fix path to target folder

.travis.yml

@@ -7,7 +7,7 @@ language: rust
 # sometimes break the build. When cache is enabled do not use the produced WASM build.
 # This also means the binary should not be used to produce the final chainspec file (because the same
 # one is embedded in the binary)
-# cache: cargo
+cache: cargo
 
 rust:
   - stable
@@ -42,7 +42,7 @@ script:
   - BUILD_DUMMY_WASM_BINARY=1 cargo clippy --release --target=${TARGET} -- -D warnings
   - BUILD_DUMMY_WASM_BINARY=1 cargo test --release --verbose --all --target=${TARGET}
   - BUILD_DUMMY_WASM_BINARY=0 WASM_BUILD_TOOLCHAIN=nightly-2020-05-23 cargo build --release --target=${TARGET} -p joystream-node
-  - ls -l target/release/wbuild/joystream-node-runtime
+  - ls -l ./target/${TARGET}/release/wbuild/joystream-node-runtime/
 
 before_deploy:
   - cp ./target/${TARGET}/release/joystream-node .