Set "use_openssl" gyp variable to 1 if it is undefined

Set "use_openssl" gyp variable to 1 if it is undefined

This CL is needed to build WebRTC without linking to BoringSSL with
use_openssl=0 in GYP_DEFINES.

BUG=
R=jiayl@chromium.org, tkchin@chromium.org

Committed: https://chromium.googlesource.com/chromium/deps/libsrtp/+/e1f6929624dd785cff493e39ab4932b955028e5c

[Satoshi Matsumoto, 2015-08-22 08:18:58]

kaorimatz@gmail.com changed reviewers:
+ jiayl@chromium.org, juberti@chromium.org

[juberti1, 2015-08-24 23:31:28]

juberti@webrtc.org changed reviewers:
+ tkchin@chromium.org

[juberti1, 2015-08-24 23:31:47]

On 2015/08/22 08:22:24, Satoshi Matsumoto wrote:

I forget the GYP syntax; Jiayang/Zeke, can you take a look at this?

[jiayl, 2015-08-24 23:45:59]

lgtm

[tkchin, 2015-08-24 23:47:31]

On 2015/08/24 23:31:47, juberti1 wrote:
> On 2015/08/22 08:22:24, Satoshi Matsumoto wrote:
> 
> I forget the GYP syntax; Jiayang/Zeke, can you take a look at this?

That is indeed what the % does. Running bots first before stamping.

[tkchin, 2015-08-24 23:47:53]

The CQ bit was checked by tkchin@chromium.org to run a CQ dry run

[tkchin, 2015-08-25 00:55:29]

On 2015/08/24 23:47:31, tkchin wrote:
> On 2015/08/24 23:31:47, juberti1 wrote:
> > On 2015/08/22 08:22:24, Satoshi Matsumoto wrote:
> > 
> > I forget the GYP syntax; Jiayang/Zeke, can you take a look at this?
> 
> That is indeed what the % does. Running bots first before stamping.

j/k apparently there's no CQ? lgtm though. jiayl@ mind submitting this? I don't
have chromium commit access.

[jiayl, 2015-08-25 16:56:45]

Committed patchset #1 (id:1) manually as
e1f6929624dd785cff493e39ab4932b955028e5c (presubmit successful).