travis: run install and tests in new shells

This had the effect of killing the travis script when a t.Fatal was hit.
As noted in the comment that was removed - a non-zero exit status makes
set -e exit, but this exits from the build script.

.travis.yml

@@ -63,12 +63,12 @@ cache:
 
 # Install the appropriate blas library (if any) and associated gonum software.
 install:
- - travis_wait 20 source ${TRAVIS_BUILD_DIR}/.travis/$TRAVIS_OS_NAME/$BLAS_LIB/install.sh
+ - travis_wait 20 ${TRAVIS_BUILD_DIR}/.travis/$TRAVIS_OS_NAME/$BLAS_LIB/install.sh
 
 script:
  - ${TRAVIS_BUILD_DIR}/.travis/check-imports.sh
  - ${TRAVIS_BUILD_DIR}/.travis/check-copyright.sh
- - source ${TRAVIS_BUILD_DIR}/.travis/$TRAVIS_OS_NAME/$BLAS_LIB/test.sh
+ - ${TRAVIS_BUILD_DIR}/.travis/$TRAVIS_OS_NAME/$BLAS_LIB/test.sh
  - test -z "$(gofmt -d .)"
  # This is run last since it alters the tree.
  - ${TRAVIS_BUILD_DIR}/.travis/check-generate.sh

.travis/linux/OpenBLAS/install.sh

@@ -1,3 +1,5 @@
+#!/bin/bash
+
 set -ex
 
 CACHE_DIR=${TRAVIS_BUILD_DIR}/.travis/${BLAS_LIB}.cache
@@ -47,13 +49,3 @@ go get -v -x gonum.org/v1/netlib/...
 
 # run the OS common installation script
 source ${TRAVIS_BUILD_DIR}/.travis/$TRAVIS_OS_NAME/install.sh
-
-# travis compiles commands in script and then executes in bash.  By adding
-# set -e we are changing the travis build script's behavior, and the set
-# -e lives on past the commands we are providing it.  Some of the travis
-# commands are supposed to exit with non zero status, but then continue
-# executing.  set -x makes the travis log files extremely verbose and
-# difficult to understand.
-# 
-# see travis-ci/travis-ci#5120
-set +ex

.travis/linux/OpenBLAS/test.sh

@@ -1,17 +1,9 @@
+#!/bin/bash
+
 set -ex
 
 go env
 go get -d -t -v ./...
 export CGO_LDFLAGS="-L/usr/lib -lopenblas"
 go test -a -v ./...
 if [[ $TRAVIS_SECURE_ENV_VARS = "true" ]]; then bash -c "$GOPATH/src/gonum.org/v1/netlib/.travis/test-coverage.sh"; fi
-
-# travis compiles commands in script and then executes in bash.  By adding
-# set -e we are changing the travis build script's behavior, and the set
-# -e lives on past the commands we are providing it.  Some of the travis
-# commands are supposed to exit with non zero status, but then continue
-# executing.  set -x makes the travis log files extremely verbose and
-# difficult to understand.
-# 
-# see travis-ci/travis-ci#5120
-set +ex