Fix reference to coveralls executable in appveyor.yml
Fix reference to coveralls executable in appveyor.yml

https://ci.appveyor.com/project/xolox/pip-accel/build/1.0.37

paylogic/pip-accel,pombredanne/pip-accel,paylogic/pip-accel,matysek/pip-accel,pombredanne/pip-accel,matysek/pip-accel