Bug#700045: linphone: account wizard rejects user names starting with a digit (required by sipgate)

[Helmut Grohne]

Package: linphone
Version: 3.5.2-10
Severity: normal

Start linphone. Click "Options", select "Preferences". Select tab
"Manage SIP Accounts". Click the "Wizard" button. Click "Forward".
Select "I have already a sip account ...". Click "Forward". Enter
arbitray 6 digits into the username field. Enter an arbitrary non-empty
character sequence into the password field. Enter a valid domain (such
as "sipgate.com") into the domain field.

Expected behaviour: The "Apply" button would be clickable.
Observed behaviour: The "Apply" button is not clickable.

Further details. The acceptance of the input data seems to depend on the
value in the username field to start with a letter. This precludes
sipgate users from using linphone.

Helmut