building may fail due to bad /var/tmp/yokozuna permissions [JIRA: RIAK-2804]

[bsoudan]

When building yokozuna on a shared machine by multiple users, the build may fail with the following error:

cp: cannot create regular file `/var/tmp/yokozuna/solr-4.7.0-yz-1.tgz': Permission denied

This happens because the tools/grab-solr.sh script creates /var/tmp/yokozuna to cache a copy of the solr tarball, but creates /var/tmp/yokozuna using the umask for the current user, which (typically) prevents other users from writing to the cache directory. If a different user tries to build and the grab-solr.sh script needs to write a tarball to the directory because their build needs a different version of solr, the build will fail with an error similar to the above.

Temporary workaround:

$ chmod 1777 /var/tmp/yokozuna

Permanent fix is ensure grab-solr.sh creates the directory with mode 1777.

[bsoudan]

See PR #692