Install miniconda in $HOME to avoid long prefix issues in conda-build 2.0

ci/travis_install_conda.sh

@@ -9,7 +9,9 @@ else
 fi
 
 wget -O miniconda.sh $MINICONDA_URL
-export MINICONDA=$TRAVIS_BUILD_DIR/miniconda
+
+export MINICONDA=$HOME/miniconda
+
 bash miniconda.sh -b -p $MINICONDA
 export PATH="$MINICONDA/bin:$PATH"
 conda update -y -q conda

ci/travis_script_python.sh

@@ -5,7 +5,7 @@ set -e
 PYTHON_DIR=$TRAVIS_BUILD_DIR/python
 
 # Re-use conda installation from C++
-export MINICONDA=$TRAVIS_BUILD_DIR/miniconda
+export MINICONDA=$HOME/miniconda
 export PATH="$MINICONDA/bin:$PATH"
 export PARQUET_HOME=$MINICONDA