[PATCHv2 2/3] travis-ci: create the cache directory early in the build process

["SZEDER Gábor" <szeder.dev@gmail.com>]

It seems that Travis CI creates the cache directory for us anyway,
even when a previous cache doesn't exist for the current build job.
Alas, this behavior is not explicitly documented, therefore we don't
rely on it and create the cache directory ourselves in those build
jobs that read/write cached data (currently only the prove state).

In the following commit we'll start to cache additional data in every
build job, and will access the cache much earlier in the build
process.

Therefore move creating the cache directory to 'ci/lib-travisci.sh' to
make sure that it exists at the very beginning of every build job.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
---
 ci/lib-travisci.sh | 2 ++
 ci/run-tests.sh    | 1 -
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/ci/lib-travisci.sh b/ci/lib-travisci.sh
index 9d379db8a..197aa14c1 100755
--- a/ci/lib-travisci.sh
+++ b/ci/lib-travisci.sh
@@ -27,6 +27,8 @@ skip_branch_tip_with_tag () {
 # and installing dependencies.
 set -ex
 
+mkdir -p "$HOME/travis-cache"
+
 skip_branch_tip_with_tag
 
 if test -z "$jobname"
diff --git a/ci/run-tests.sh b/ci/run-tests.sh
index f0c743de9..ccdfc2b9d 100755
--- a/ci/run-tests.sh
+++ b/ci/run-tests.sh
@@ -5,6 +5,5 @@
 
 . ${0%/*}/lib-travisci.sh
 
-mkdir -p $HOME/travis-cache
 ln -s $HOME/travis-cache/.prove t/.prove
 make --quiet test
-- 
2.16.0.rc0.67.g3a46dbca7