tests(sharness) attempt to execute sharness tests on ipfs2

@jbenet @chriscool

(not to be merged into master) This is a hack to run sharness tests on
th ipfs2 binary. Instead of compiling cmd/ipfs, it compiles cmd/ipfs2
and copies this into test/bin/ipfs.

I thought this would be enough to pass the `basic-commands` test, but
it's not.

Although the output is fairly similar, the `ipfs version` test fails.

```
test (feat/test2) λ. diff version1 version2
1c1
< ipfs version 0.1.7
---
> ipfs version 0.1.5
```

I'm not very experienced with `sh` scripting, so perhaps I'm missing a
key ingredient or maybe misunderstanding the the tests are meant to
work.

Would like to get input on this.

Thanks, @maybebtc
fix(2/version) make it possible to execute before init

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>
Adapt t0040 to output from ipfs2

The ouput from "ipfs add" changed in ipfs2.
With the changes in this commit, this output change doesn't
prevent the test to pass.

With TEST_NO_FUSE=1 test t0040 now passes on my Linux machine.

License: MIT
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Adapt t0050 to output from ipfs2

The ouput from "ipfs block" changed in ipfs2.
With the change in this commit, this output change doesn't
prevent the test to pass.

Test t0050 now passes on my Linux machine.

License: MIT
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Adapt t0010 to output from ipfs2

The ouput from "ipfs help" changed in ipfs2.
With the change in this commit, this output change doesn't
prevent the test to pass.

Test t0010 now passes on my Linux machine.

License: MIT
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Adapt mount tests to ipfs2 changes

License: MIT
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Merge branch 'feat/ipfs2-test_sharness'