Fixed bugs in multi-GPU clover calculation.

Previously, the field-strength dimensions were set using the extended gauge field,
but the field strength is not extended.

Switched to QUDA_RECONSTRUCT_NO for the extended gauge field since copyExtendedGauge
does not support link reconstruction in the output field.

Included factor of two in clover reconstruction kernel. Note that our
definition of the clover coefficient differs from Alexandro's by a factor of 2.

Added clover_coeff member variable to QudaInvertParam_s