DAVdroid crashes when using wrong values in the SIP address field

[devvv4ever]

DAVdroid crashes when using wrong values in the SIP address field in the contacts app.

Steps to reproduce:

• Edit a contact
• Add "internet call" field
• enter "Skype: blahblah" as value
• Force a sync

DAVdroid crashes unexpectedly.

[devvv4ever]

For Skype please use the appropriate field for "Instant messenger" or "Chat". There is a label named Skype there.