travis/get-*: fail build earlier on problems

.travis/get-anaconda.sh

@@ -1,6 +1,8 @@
 #!/bin/sh
 # Copyright (C) 2014, 2015 Robert Jordens <jordens@gmail.com>
 
+set -e
+
 export PATH=$HOME/miniconda/bin:$PATH
 wget http://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O miniconda.sh
 bash miniconda.sh -b -p $HOME/miniconda

.travis/get-toolchain.sh

@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -e
+
 packages="http://us.archive.ubuntu.com/ubuntu/pool/universe/i/iverilog/iverilog_0.9.7-1_amd64.deb"
 
 mkdir -p packages

.travis/get-xilinx.sh

@@ -2,6 +2,8 @@
 # Copyright (C) 2014, 2015 M-Labs Limited
 # Copyright (C) 2014, 2015 Robert Jordens <jordens@gmail.com>
 
+set -e
+
 wget http://sionneau.net/artiq/Xilinx/xilinx_ise_14.7_s3_s6.tar.gz.gpg
 echo "$secret" | gpg --passphrase-fd 0 xilinx_ise_14.7_s3_s6.tar.gz.gpg
 tar -C $HOME/ -xzf xilinx_ise_14.7_s3_s6.tar.gz