Ensure cnf/cache/ folder is present upon git checkout

We adjust the .gitgnores by placing a .gitignore file in the cnf/cache/
folder. We need the folder always present, so we can locally cache the
cloudbees bundles for bnd.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Use ${build} instead of ${workspace}/cnf

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Cache bnd repo in cnf/cache/

Caching in the default location of ~/.bnd/cache caused some build
failures because the bnd repo changes for each bnd build and that upset
the repo logic occasionally.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Use bnd_repourl in gradle.properties as the location of the bnd repo build

This allows the repo url to be externally set in the CI build with the
gradle command line option -Pbnd_repourl=<url>.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Merge pull request #939 from bjhargrave/locally-cache-cloudbees

Locally cache cloudbees

Caching in the default location of ~/.bnd/cache caused some build
failures because the bnd repo changes for each bnd build and that upset
the repo logic occasionally.