Made cross-checks before retrieving data content
Merge branch 'master' of github.com:dmwm/DAS
fix dataset wildcard and KWS tests

* text has chainged in wildcard exception messages, made tests more generic
* in KWS, schema adapter now requires an instance of DASCore (and do not create it if it was not initialized beforehand)
added google_maps service to default config

* it is used in unit tests, will will fix these tests from failing with default config
pass unit test if some json module works

* this makes the unit tests to pass if at least one json module passes all tests, but some other json modules are not available
* still, the error messages are made available for inspecting visually
* still in future we might have a flag which says if we are requiring all tests to pass
pylint/pep8 fixes for test/jsonwrapper_t.py
Merge pull request #4080 from dmwm/fix_das_tests

Improve the tests slightly: dataset wildcard, jsonwrapper, tests based on zip service
Merge branch 'master' of github.com:dmwm/DAS
fix clean_worker to respect expiration timestamps

* spec must be passed as a positional arg to collection.remove
* otherwise, passing a kwarg removes EVERYTHING from the collection, i.e. each time cleanup_worker was run, it would wipe whole collection!

fixes issue #4082
Merge pull request #4083 from dmwm/cleanup_worker_fix

fix clean_worker to respect expiration timestamps
Fix issue 4085
Switch to use QLManager instead of singleton instance, should help interminnent problem with DAS parser
Update
Reverse back usage of singleton since server takes too much time to initialize QLManager during concurrent request. We should revisit this and possibly create pool of QLManagers
Introduce custom find_one helper function which immitates MongoDB one. It uses exhaust option. Allow acquire of DB connection via small loop (if something happens first time, let it few more trials)
Replace MognoDB find_one calls with custom one
Replace MognoDB find_one calls with custom one
Replace MognoDB find_one calls with custom one
Replace MognoDB find_one calls with custom one
Replace MognoDB find_one calls with custom one