lisa/trace: Fix dataframe prefiltering for userspace ftrace events
It looks like the appearance of userspace generated ftrace events has changed. What appears to be memory address 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.
:'.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.