Fix symmetry contribution unit test so that it doesn't reload RMG database
Fix symmetry contribution unit test so that it doesn't reload RMG database

It made unit tests very slow to run.

enochd/RMG-Py,nickvandewiele/RMG-Py,nickvandewiele/RMG-Py,pierrelb/RMG-Py,nyee/RMG-Py,enochd/RMG-Py,pierrelb/RMG-Py,chatelak/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py