Convert iOS try bots to Xcode 5.1 instead of 5.1.1

Convert iOS try bots to Xcode 5.1 instead of 5.1.1

They only have 5.1 installed

BUG=460930
Committed: https://crrev.com/bc410bea994b1e3590be57960c9d5bfa7cd7020b
Cr-Commit-Position: refs/heads/master@{#317636}

[smut, 2015-02-23 19:05:53]

smut@google.com changed reviewers:
+ lliabraa@chromium.org, sergeyberezin@google.com, stuartmorgan@chromium.org

[smut, 2015-02-23 19:05:54]

FYI and Main had 5.1.1 installed, try only has 5.1.

[Sergey Berezin, 2015-02-23 19:08:48]

sergeyberezin@chromium.org changed reviewers:
+ sergeyberezin@chromium.org

[Sergey Berezin, 2015-02-23 19:08:48]

Note that some trybots apparently have 5.1.1 (they succeed), while others have
5.1. Will this work for both versions?

[smut, 2015-02-23 19:19:18]

On 2015/02/23 19:08:48, Sergey Berezin wrote:
> Note that some trybots apparently have 5.1.1 (they succeed), while others have
> 5.1. Will this work for both versions?

By itself no, we'll need https://codereview.chromium.org/950973002 as well.

[stuartmorgan, 2015-02-23 19:24:45]

LGTM as a temporary measure. Presumably we've been silently living with 5.1 bots
for a while anyway...

[Sergey Berezin, 2015-02-23 19:29:11]

LGTM. And in addition, https://codereview.chromium.org/940473003 until the
builder is proven to work well.

[smut, 2015-02-23 19:33:30]

The CQ bit was checked by smut@google.com

[commit-bot: I haz the power, 2015-02-23 19:34:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/947273002/1

[commit-bot: I haz the power, 2015-02-23 20:03:39]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-23 20:04:31]

Patchset 1 (id:??) landed as
https://crrev.com/bc410bea994b1e3590be57960c9d5bfa7cd7020b
Cr-Commit-Position: refs/heads/master@{#317636}