ci: work around ccache segafult during setup

This is the same fix we applied for the macOS. Somehow ccache segfaults
during the init. This only shows on the Ubuntu 19.10 update.

Reviewed-by: Marcel Hollerbach <mail@marcel-hollerbach.de>
Differential Revision: https://phab.enlightenment.org/D10599

.ci/docker-ccache-setup.sh

@@ -7,5 +7,6 @@ cp .ci/ccache.conf ~/.ccache
 if [ "$1" = "release-ready" ] ; then
   ccache -o base_dir="$(pwd)/$(grep '^PACKAGE_STRING' config.log|cut -d\' -f2|tr ' ' -)"
 else
-  ccache -o base_dir=$(pwd)
+  sed -iE '/^base_dir/d' ~/.ccache/ccache.conf
+  echo "base_dir = $pwd" >> ~/.ccache/ccache.conf
 fi