travis: Check that ~/.bitcoin is never created

Author: MarcoFalke

.travis.yml

@@ -53,6 +53,7 @@ install:
     - travis_retry DOCKER_EXEC apt-get update
     - travis_retry DOCKER_EXEC apt-get install --no-install-recommends --no-upgrade -qq $PACKAGES $DOCKER_PACKAGES
 before_script:
+    - DOCKER_EXEC echo \> \$HOME/.bitcoin  # Make sure default datadir does not exist and is never read by creating a dummy file
     - mkdir -p depends/SDKs depends/sdk-sources
     - if [ -n "$OSX_SDK" -a ! -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then curl --location --fail $SDK_URL/MacOSX${OSX_SDK}.sdk.tar.gz -o depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi
     - if [ -n "$OSX_SDK" -a -f depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz ]; then tar -C depends/SDKs -xf depends/sdk-sources/MacOSX${OSX_SDK}.sdk.tar.gz; fi