CMake: Also set CSYNC_BINARY_DIR

...so NSIS finds its resource in the right place.

cmake/modules/FindCsync.cmake

@@ -12,6 +12,7 @@ IF( DEFINED CSYNC_LIBRARY_PATH AND DEFINED CSYNC_INCLUDE_PATH )
   ELSE()
     SET(CSYNC_LIBRARY ${CSYNC_LIBRARY_PATH}/src/libocsync.so)
   ENDIF( )
+  SET(CSYNC_BINARY_DIR ${CSYNC_LIBRARY_PATH})
 ELSE()
   FIND_LIBRARY(CSYNC_LIBRARY NAMES ocsync HINTS $ENV{CSYNC_DIR})
 ENDIF()