conversation: reduice the history call lenght

In the conversation fragment, the ringID is displayed for each call
history but this information is already displayed on the top.
This commit only displays the call status and the date in the history.

Change-Id: I5ec19568aec075b4edd0cba88ddaa6aeb5cdef59
Reviewed-by: Hadrien De Sousa <hadrien.desousa@savoirfairelinux.com>