Fix a few races

- GlobusPathMatchingResourcePatternResolver is not reusable and should thus
  be recreated every time it is needed

- AbstractResourceSecurityWrapper#refresh was not thread safe

The patch addresses these issues and in the process cleans up the construction
of AbstractResourceSecurityWrapper objects.
ssl-proxies: Refactor ResourceSecurityWrapperStore

Simplifies and optimizes the code and fixes potential race conditions.
ssl-proxies: Fix races in PEMKeyStore
Merge pull request #115 from gbehrmann/fix/securitywrapper

Fix a few races