Fix for JRuby lazy creation.

By mistake, commit b68e61dc35ddd84a933926c14c760cfe6e472af5 made
JRuby container creation to be non-lazy.

This fixes it, and simplifies it by introducing a
lazy provider that also cleans up.
[NEXUS-6790] Copy yum metadata to group in case of a single yum member

commit 733115040ee852a206e25fc8ed822c3d733cd9fb
Author: Alin Dreghiciu <adreghiciu@gmail.com>
Date:   Tue Oct 21 19:09:31 2014 +0300

    [NEXUS-6790] Fix test about conccurent running of MergeMetadataTask

commit 23886a203b7860cc04280dd5d68a00af474b4a23
Author: Alin Dreghiciu <adreghiciu@gmail.com>
Date:   Tue Oct 21 18:59:04 2014 +0300

    [NEXUS-6790] Only copy when there is exactly one member

commit 3be3e20300823cfc6f22db89ab82282f33736665
Author: Alin Dreghiciu <adreghiciu@gmail.com>
Date:   Tue Oct 21 18:19:34 2014 +0300

    [NEXUS-6790] Copy yum metadata to group in case of a single yum member
Merge pull request #811 from sonatype/fix-jruby-lazy-creation

Fix for JRuby lazy creation.
Logging JRuby container creation at INFO level
Moving ruby related gitattribute change closer to where it's used
use less ruby in tests and hopefully eliminating last place where 'Errno::EBADF: Bad file descriptor' happened
NEXUS-7517: Added more logging and helpers

Added logging to the two central component (facade and storage)
and introduced log config helpers.
Cleanup, call method instead going to extt config
set metadata max age to practical default
verify the expiration of volatile dependencies files on proxy
Override client's maxAges with rubygem specific ones
Merge pull request #809 from mkristian/volatile-files

Volatile files
Merge pull request #813 from sonatype/nexus-2.11.x-NEXUS-7517-add-more-logging

NEXUS-7517: Added more logging and helpers
fix regex to avoid "BUG" log entries
Merge pull request #814 from mkristian/trivial

fix regex to avoid "BUG" log entries
Cleanups.

Some javadoc, some modifiers, some try-catch-with resource
to eliminate use of close calls, and synced formatter
access in AbstractMetadataBuilder.
Merge remote-tracking branch 'origin/nexus-2.11.x' into nexus-2.11.x-NEXUS-7596-check-createrepo

Conflicts:
	plugins/yum/nexus-yum-repository-plugin/src/main/java/org/sonatype/nexus/yum/internal/task/MergeMetadataTask.java