Remove a forgotten instance of @libsuffix@
* lang/cpp/src/GpgmeppConfig.cmake.in.in: Remove a forgotten instance of @libsuffix@.
b2c07bd47bd608afa5cc819b60a7b5bb8c9dd96a removed @libsuffix@ from
cmake config files, but missed one instance.
- Signed-off-by: Heiko Becker <heirecka@exherbo.org>