As this file is use by dh_dkms, it's Ok to adjust it just before calling dh_dkms. Also, the option '-V $(DEB_VERSION_UPSTREAM)' is pointless, as we already made sure that PACKAGE_VERSION was set properly.
realtek-rtl8188eus DKMS module for Debian This package was automatically generated by the DKMS system, for distribution on Debian based operating systems.