net/http: TestClientTrailers_h2 is failing

[bradfitz]

TestClientTrailers_h2 is marked skipped for now.

Fix.

[gopherbot]

CL https://golang.org/cl/17683 mentions this issue.

[gopherbot]

CL https://golang.org/cl/17891 mentions this issue.

[gopherbot]

CL https://golang.org/cl/17895 mentions this issue.

[gopherbot]

CL https://golang.org/cl/17931 mentions this issue.

[gopherbot]

CL https://golang.org/cl/17930 mentions this issue.

[gopherbot]

CL https://golang.org/cl/17935 mentions this issue.