Prevent NPEs when Ofile has no hasher

Integration tests were failing with NPEs:

```
InternalException: exception ::omero::InternalException
{
    serverStackTrace = java.lang.NullPointerException
    at ome.services.blitz.repo.RepositoryDaoImpl.fileContext(RepositoryDaoImpl.java:838)
    at ome.services.blitz.repo.RepositoryDaoImpl.getRawFileStore(RepositoryDaoImpl.java:144)
    at ome.services.blitz.repo.PublicRepositoryI.createRepoRFS(PublicRepositoryI.java:467)
    at ome.services.blitz.repo.PublicRepositoryI.file(PublicRepositoryI.java:370)
```
caused by an inner join on originalfile.hasher. Since
the field is nullable, this needs to be a left outer join.
Move algorithm lookup after null file check

NPEs were being thrown due to the getOriginalFile call
before checking the `FsFile` for nullness:

```
UnknownException: exception ::Ice::UnknownException
{
    unknown = java.lang.NullPointerException
    at ome.services.blitz.repo.PublicRepositoryI.checkId(PublicRepositoryI.java:676)
    at ome.services.blitz.repo.PublicRepositoryI.fileById(PublicRepositoryI.java:374)
```
fix testDoubleDot integration test
fix testBasicUsage integration test

This fix is very temporary to reveal which tests still fail.
When setting OriginalFile hasher clear the hash field.

Shouldn't actually change behavior at all given the current code paths.
Merge pull request #1151 from mtbc/josh-tests

Hasty fixes for FS integration tests