perf flame graph: fixed tooltips

[asheplyakov]

app/perf/flame_graph.py now uses the same naming as nflxprofile

Closes: #124

[asheplyakov]

CI jobs are failing since MarkupSafe==1.0 fails to install with setuptools<=44

Collecting MarkupSafe==1.0
  Downloading MarkupSafe-1.0.tar.gz (14 kB)
    ERROR: Command errored out with exit status 1:
     command: /home/travis/virtualenv/python3.6.7/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-c3bmpo5u/MarkupSafe/setup.py'"'"'; __file__='"'"'/tmp/pip-install-c3bmpo5u/MarkupSafe/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-vh96rfet
         cwd: /tmp/pip-install-c3bmpo5u/MarkupSafe/
    Complete output (5 lines):
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-install-c3bmpo5u/MarkupSafe/setup.py", line 6, in <module>
        from setuptools import setup, Extension, Feature
    ImportError: cannot import name 'Feature'
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.