Increase conda download retries (#3857)

* Increase conda download retries

We've been seeing an increase in conda download failures on travis
lately. After talking to the conda team, it was suggested to try
increasing the value of `remote_max_retries` to 10 to see if that helps
(they're not 100% sure why this would be happening).

* Error on install failure

Previously the error would only happen at runtime. Should make debugging
a bit easier.

continuous_integration/hdfs/install.sh

@@ -1,2 +1,6 @@
+set -xe
+
 docker exec -it $CONTAINER_ID conda install -y -q dask hdfs3 pyarrow -c twosigma -c conda-forge
 docker exec -it $CONTAINER_ID pip install -e .
+
+set +xe

continuous_integration/travis/install.sh

@@ -1,3 +1,5 @@
+set -xe
+
 #!/usr/bin/env bash
 # Install conda
 case "$(uname -s)" in
@@ -14,7 +16,7 @@ esac
 wget https://repo.continuum.io/miniconda/$MINICONDA_FILENAME -O miniconda.sh
 bash miniconda.sh -b -p $HOME/miniconda
 export PATH="$HOME/miniconda/bin:$PATH"
-conda config --set always_yes yes --set changeps1 no
+conda config --set always_yes yes --set changeps1 no --set remote_max_retries 10
 
 # Create conda environment
 conda create -q -n test-environment python=$PYTHON
@@ -113,3 +115,5 @@ fi;
 pip install --no-deps -e .[complete]
 echo conda list
 conda list
+
+set +xe