dist.sh and Godeps updates

[ploxiln]

I ran into some problems running dist.sh on my system (OS X 10.11, go-1.8, gpm-1.4.0, git-2.12.1).

>> Setting github.com/18F/hmacauth to version 1.0.1
/usr/local/bin/gpm: line 73: cd: /Users/pierce/scratch/oauth2_proxy/.godeps/src/github.com/18F/hmacauth: No such file or directory
>> Setting github.com/BurntSushi/toml to version 3883ac1ce943878302255f538fce319d23226223
/usr/local/bin/gpm: line 73: cd: /Users/pierce/scratch/oauth2_proxy/.godeps/src/github.com
 (... repeated for all deps, not a showstopper, build succeeds)

>> Setting golang.org/x/oauth2 to version 04e1573abc896e70388bd387a69753c378d46466
>> Setting golang.org/x/oauth2/google to version 04e1573abc896e70388bd387a69753c378d46466
>> Setting google.golang.org/api/admin/directory/v1 to version a5c3e2a4792aff40e59840d9ecdff0542a202a80
fatal: Unable to create '/Users/pierce/scratch/oauth2_proxy/.godeps/src/golang.org/x/oauth2/.git/index.lock': File exists.

Another git process seems to be running in this repository, e.g.
an editor opened by 'git commit'. Please make sure all processes
are terminated then try again. If it still fails, a git process
may have crashed in this repository earlier:
remove the file manually to continue.

>> Getting package golang.org/x/oauth2
>> Getting package golang.org/x/oauth2/google
>> Getting package google.golang.org/api/admin/directory/v1
# cd .; git clone https://go.googlesource.com/oauth2 /Users/pierce/scratch/oauth2_proxy/.godeps/src/golang.org/x/oauth2
Cloning into '/Users/pierce/scratch/oauth2_proxy/.godeps/src/golang.org/x/oauth2'...
error: Untracked working tree file '.travis.yml' would be overwritten by merge.
fatal: unable to checkout working tree
warning: Clone succeeded, but checkout failed.
You can inspect what was checked out with 'git status'
and retry the checkout with 'git checkout -f HEAD'

package golang.org/x/oauth2: exit status 128

.godeps/src/golang.org/x/oauth2/google/default.go:17:2: cannot find package "cloud.google.com/go/compute/metadata" in any of:
	/usr/local/Cellar/go/1.8/libexec/src/cloud.google.com/go/compute/metadata (from $GOROOT)
	/Users/pierce/scratch/oauth2_proxy/.godeps/src/cloud.google.com/go/compute/metadata (from $GOPATH)
	/Users/pierce/go/src/cloud.google.com/go/compute/metadata

With the commits in this PR, dist.sh runs cleanly for me (except the test "TestRequestSignaturePostRequest" fails with a sha1 signature mismatch but I'm guessing that's unrelated). Apologies if these problems are caused by my system/setup somehow.

[ploxiln]

looks like google.golang.org/grpc only supports back to go-1.6:

$ ls .godeps/src/google.golang.org/grpc/transport/ | grep ^go
go16.go
go17.go

[ploxiln]

looks like the test failure is unique to go-1.8 somehow

[ploxiln]

also, the go-1.5.x compat problem is because not all deps were tracked by gpm

[jehiah]

Thanks @ploxiln. The signed request failure with 1.8 is odd but i'll work on a fix for that separately. These changes look good.

[ploxiln]

I was working on adding some of the indirect dependencies to Godeps and ran into strange gpm get failures with the golang.org/x/net and golang.org/x/text trees, I think due to gpm go-getting them in parallel (e.g. diamond dependency graph, go get of multiple google libs at the same time get /x/net at the same time). Just a note for future attempts.