No back key to return to the country list when authentication

[Jin]

Description:
Telegram has no way to return to the country list when user is doing the authentication.

Reproduce Steps:
    a) Launch Telegram (first start)
    b) Press "Start Messaging"
    c) Select the country code
    d) Observe the "Phone Number" page

Expected Result:
Telegram has a back key in the top bar to return to previous countries list.

Actual Result:
Telegram has no back key to return to previous page for correcting the countries if user input a wrong one.

Occurrence:
10/10 (100%)

Software Information:
    com.ubuntu.telegram (2.2.10.0)

Hardware Information:
    current build number: 430
    device name: mako
    channel: ubuntu-touch/rc-proposed/ubuntu
    last update: 2016-05-06 15:09:42
    version version: 430
    version ubuntu: 20160505
    version device: 20160401.1
    version custom: 20160505

[Jin (jindallo)]

I confirmed this bug,
thanks for this report, Paz!

[Jin (jindallo)]

Bug fixed,
and verified pass on developer side.

The change list is submitted as rev. 187,
below is the detail information.
    http://bazaar.launchpad.net/~libqtelegram-team/telegram-app/telegram/revision/187

Device Information:
    current build number: 439
    device name: mako
    channel: ubuntu-touch/rc-proposed/ubuntu
    last update: 2016-05-13 14:51:20
    version version: 439
    version ubuntu: 20160513
    version device: 20160401.1
    version custom: 20160513
    version custom: 20160408.3