Saving to svg fails with use of textcomp character

The following code (under standard packages of Ubuntu 15.04)

from pylab import *
pp={'text.usetex': True,
           'text.latex.unicode': True,
           }
rcParams.update(pp)

plot(1,1)
ylabel(r'\textwon')
savefig('tmp.pdf')
print('Saved pdf')
savefig('tmp.png')
print('Saved png')
savefig('tmp.svg')
print('Saved svg')

gives output:

Saved pdf
Saved png
/usr/lib/python2.7/dist-packages/matplotlib/textpath.py:387: UserWarning: The glyph (142) of font (/usr/share/texmf/fonts/type1/public/cm-super/sfrm3583.pfb) cannot be converted with the encoding. Glyph may be wrong
  "be wrong" % (glyph, font_bunch.filename))
Saved svg

While the files pdf and png have the \textwon character properly rendered, it is missing from the svg.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: python-matplotlib 1.4.2-3.1
ProcVersionSignature: Ubuntu 3.19.0-10.10-generic 3.19.2
Uname: Linux 3.19.0-10-generic x86_64
ApportVersion: 2.16.2-0ubuntu5
Architecture: amd64
CurrentDesktop: Unity
Date: Mon Mar 30 11:24:28 2015
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-03-28 (1 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Beta amd64 (20150325)
SourcePackage: matplotlib
UpgradeStatus: No upgrade log present (probably fresh install)