becker33 8ae380fb71 Fixes for parsing specs with hashes (#2889) ...

- Allows hashes to be specified after other parts of the spec
- Does not allow other parts of the spec to be specified after the hash
- The hash must either end input or be followed by another separate spec
- The next spec cannot be an anonymous spec (it must start with a package name or a hash)

See #2769 (after it was merged) for further discussion of this interface addition. That discussion resulted in these requirements:

```
python                     # 1 spec
/abc123                    # 1 spec
python /abc123             # 1 spec
/456789                    # 1 spec
python /abc123 /456789     # 2 specs
python /456789 /abc123     # 2 specs
/abc123 /456789            # 2 specs
/456789 /abc123            # 2 specs
/456789 /abc123 python     # 3 specs
```

assuming `abc123` and `456789` are both hashes of different python specs.

2017-01-25 21:38:10 -07:00

..

spack

Fixes for parsing specs with hashes (#2889)

2017-01-25 21:38:10 -07:00