deps: update libuv to 1.2.1

[saghul]

R=@piscisaureus, @bnoordhuis

I got the following test failure, looks unrelated:

$ make test-simple 
ninja -v -C out/Release/
ninja: Entering directory `out/Release/'
ninja: no work to do.
ln -fs out/Release/iojs iojs
/usr/bin/python tools/test.py parallel sequential
=== release test-debug-signal-cluster ===                                      
Path: parallel/test-debug-signal-cluster
> all workers are running
> Starting debugger agent.
> Debugger listening on port 12388
> Starting debugger agent.
> Debugger listening on port 12390
got pids [25485,25491,25497]

assert.js:100
  throw new assert.AssertionError({
        ^
AssertionError: 4 == 6
    at assertOutputLines (/home/saghul/src/io.js/test/parallel/test-debug-signal-cluster.js:80:10)
    at onNoMoreLines [as _onTimeout] (/home/saghul/src/io.js/test/parallel/test-debug-signal-cluster.js:48:3)
    at Timer.listOnTimeout (timers.js:90:15)
Command: out/Release/iojs /home/saghul/src/io.js/test/parallel/test-debug-signal-cluster.js
[02:45|% 100|+ 771|-   1]: Done                                                
Makefile:144: recipe for target 'test-simple' failed
make: *** [test-simple] Error 1

[bnoordhuis]

parallel/test-debug-signal-cluster is a timing sensitive test, it's being tracked in #340. Waiting for the CI to finish: https://jenkins-iojs.nodesource.com/view/iojs/job/iojs+any-pr+multi/76/

[piscisaureus]

https://jenkins-iojs.nodesource.com/job/iojs+any-pr+multi/77/

[piscisaureus]

lol, race condition

[piscisaureus]

Thanks @saghul, landed in 07bd05b.