Bugfix in Chebyshev.fitToData() unit test.
Bugfix in Chebyshev.fitToData() unit test.

The method being tested was actually correct, but the unit test itself
was incorrect, causing it to fail. This commit fixes the bug (a units
error, naturally).

nyee/RMG-Py,nickvandewiele/RMG-Py,comocheng/RMG-Py,enochd/RMG-Py,enochd/RMG-Py,comocheng/RMG-Py,KEHANG/RMG-Py,faribas/RMG-Py,KEHANG/RMG-Py,pierrelb/RMG-Py,pierrelb/RMG-Py,chatelak/RMG-Py,chatelak/RMG-Py,faribas/RMG-Py,nickvandewiele/RMG-Py,nyee/RMG-Py