[build] travis: remove existing conda dir

there seems to be a caching issue at the moment;
this is a temporary fix for #3786

diff --git a/scripts/travis/travis_install.sh b/scripts/travis/travis_install.sh
index ca8c410..091e924 100755 (executable)
--- a/scripts/travis/travis_install.sh
+++ b/scripts/travis/travis_install.sh
@@ -60,6 +60,8 @@ rm -f $LMDB_FILE
 # Install the Python runtime dependencies via miniconda (this is much faster
 # than using pip for everything).
 export PATH=$CONDA_DIR/bin:$PATH
+# clear any cached conda (see #3786)
+rm -rf $CONDA_DIR
 if [ ! -d $CONDA_DIR ]; then
   if [ "$PYTHON_VERSION" -eq "3" ]; then
     wget http://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O miniconda.sh