Use correct strings for DLL VersionInfo

Use correct strings for DLL VersionInfo

Previous DLL build reported FileVersion as literally
"PACKAGE_VERSION_DLL" instead of expanding the macro because of the
quotes. Also reported original filename as "wpcap.dll" regardless of
library name configured via CMake.

This change also preserves the "libpcap" product name, since regardless
of the library name configured, the code is still the libpcap product.

(cherry picked from commit b51f5e88096415fa5e53e32909ae784af261b253)