Fix text logcat for changes in android L

In L, in line "-- beginning of /<buffer>" the "/" was removed.
This commit accomodates text logcat to that change.

Change-Id: I4cbfadf5a8169589f2848ce1a5793cea593ba459
Reviewed-on: https://code.wireshark.org/review/5405
Petri-Dish: Michal Labedzki <michal.labedzki@tieto.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Michal Labedzki <michal.labedzki@tieto.com>