add doSNOW package to R 3.2.3 easyconfigs

[boegel]

No description provided.

[boegel]

Test report by @boegel
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in this PR)
node2090.delcatty.os - Linux SL 6.7, Intel(R) Xeon(R) CPU E5-2670 0 @ 2.60GHz, Python 2.6.6
See https://gist.github.com/19f1f8d45985ab55f05d for a full test report.

[boegel]

Test report by @boegel
SUCCESS
Build succeeded for 2 out of 2 (2 easyconfigs in this PR)
node2668.swalot.os - Linux centos linux 7.2.1511, Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz, Python 2.7.5
See https://gist.github.com/dfc75fdac740846b257d for a full test report.

[hpcugentbot]

Easyconfigs unit test suite PASSed (see https://jenkins1.ugent.be/job/easybuild-easyconfigs-pr-builder/6842/console for more details).

This pull request is now ready for review/testing.

Please try and find someone who can tackle this; contact @boegel if you're not sure what to do.

[boegel]

trivial, going in...