Restore recursive mkdir on LOG_DIR

Revert part of 2bcd901a9e60f24a4c1c972bc3354969a8c8258e.
Up to three levels of directories may need to be created, if a user only
defines STORAGE_DIR and uses the --instance parameter.

Now, if you want every subdir under LOG_DIR to be owned by USER, you
must create all but the last directory beforehand and give it the
correct owner. Automatically chown()'ing each level of directory created
would have been too complicated.

Fixes #199.
Merge pull request #202 from jamesjuran/fix_log_mkdir

Restore recursive mkdir on LOG_DIR
Force exact match of regex_pattern for carbon-aggregator rules.

In its current implementation the regex_pattern would match any metric that starts with the given pattern. Consider the following rules:

aggregated.histogram.p99        (10) = avg hosts.*.histogram.p99
aggregated.histogram.p999       (10) = avg hosts.*.histogram.p999

Currently the second rule would be treated as expected but the first rule would lead to an aggegated metric `aggregated.histogram.p99` which would in fact be equivalent to `avgSeries(hosts.*.histogram.p99,hosts.*.histogram.p999)`.

This patch forces exact matches of the regex_pattern, not only prefix-matches.
Merge pull request #120 from ctavan/aggregator-regex-pattern-end

Fix regex_pattern for carbon-aggregator rules.
Merge branch 'master' of https://github.com/graphite-project/carbon