Math font warnings

Hi, list. Whenever I use matplotlib, I see the following set of
warnings:

/usr/lib64/python2.7/site-packages/matplotlib/font_manager.py:1242:
UserWarning: findfont: Font family ['cmb10'] not found. Falling back to
Bitstream Vera Sans
  (prop.get_family(), self.defaultFamily[fontext]))
/usr/lib64/python2.7/site-packages/matplotlib/font_manager.py:1252:
UserWarning: findfont: Could not match :family=Bitstream Vera
Sans:style=normal:variant=normal:weight=normal:stretch=normal:size=12.0.
Returning /usr/share/matplotlib/mpl-data/fonts/ttf/STIXGeneral.ttf
  UserWarning)
/usr/lib64/python2.7/site-packages/matplotlib/font_manager.py:1242:
UserWarning: findfont: Font family ['cmtt10'] not found. Falling back to
Bitstream Vera Sans
  (prop.get_family(), self.defaultFamily[fontext]))
/usr/lib64/python2.7/site-packages/matplotlib/font_manager.py:1242:
UserWarning: findfont: Font family ['cmss10'] not found. Falling back to
Bitstream Vera Sans
  (prop.get_family(), self.defaultFamily[fontext]))

They don't seem to affect my output, but I looked into it anyway. It
turns out that the texcm-ttf package installed by most distributions
only includes a handful of fonts (cmex10.ttf, cmmi10.ttf, cmr10ttf,
cmsy10.ttf). I was able to get rid of the warnings by manually
installing the missing fonts from
http://tug.ctan.org/tex-archive/fonts/cm/ps-type1/bakoma/ttf/

Should distributions be installing the rest of the TeX fonts like I did?
Is there another way to avoid these warnings? Thanks.

Markus