vhost-plugin: switch from rewrite back to proxypass

Switch the primary traffic proxy for the vhost frontend plugin.
There are still other RewriteRule's that do the setting of
variables, etc.
Multiple fixes for stability
 - Adding option to prevent rollback in case of successful execution of a destructive operation that is not reversible (deleting gear or deconfiguring cartridge on the node)
 - Checking for the existence of the application after obtaining the lock
 - Reloading the application after acquiring the lock to reflect any changes made by the previous operation holding the lock
 - Using regular run_jobs code in clear-pending-ops script
 - Handling DocumentNotFound exception in clear-pending-ops script if the application is deleted
Checking for empty string in ObjectId
Deleting applications on app creation rollbacks
Clean up model objects after test
Bug 1073413 - Fix versions in nodejs upgrade script
Merge pull request #4912 from liggitt/test_clean_up

Merged by openshift-bot
Require -recommended metapackages from -optional cart deps

Most users will want the recommended cartridge dependencies when
installing the optional cartridge dependency metapackage(s).
Added max_teams capability
Merge pull request #4913 from mfojtik/bugzilla/1073413

Merged by openshift-bot
Merge pull request #4857 from lnader/master

Merged by openshift-bot
Merge pull request #4916 from dobbymoodge/opt-req-rec

Merged by openshift-bot
Merge pull request #4840 from abhgupta/abhgupta-dev

Merged by openshift-bot
Removing f19 logic
Merge pull request #4918 from danmcp/master

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Create less apps in tests
Merge pull request #4919 from danmcp/master

Merged by openshift-bot
Make nodejs watch just a single file by default instead of REPO_DIR
Refactor the way how we check if compilation of assets is necessary (ruby)
Merge pull request #4904 from mfojtik/card_156

Merged by openshift-bot