lisa.trace: Fix dataframe prefiltering for userspace ftrace events

FIX

It looks like the appearance of userspace generated ftrace events has
changed. What appears to be a compiler ID hash has been added to the event
meta data breaking the prefiltering of trace data in
_select_userspace().

The event used contain the keyword 'tracing_mark_write:', but now has
the format: 'tracing_mark_write.<ID_hash>:'.

Example:
   rt-app-21908 [001] 4470442.464974: print:
tracing_mark_write.10e87ffbd993ed977ebcbff93a794b6d: rtapp_main:
event=end

Fix the event filtering to handle new format without breaking backwards
compatibility.