Fixed versioning bug: FIND_PACKAGE( OpenCV ) errors if no version specified

OpenCVConfig-version.cmake.in

@@ -4,11 +4,11 @@ set(PACKAGE_VERSION ${OpenCV_VERSION})
 set(PACKAGE_VERSION_EXACT False)
 set(PACKAGE_VERSION_COMPATIBLE False)
 
-if(${PACKAGE_FIND_VERSION} VERSION_EQUAL ${PACKAGE_VERSION})
+if("${PACKAGE_FIND_VERSION}" VERSION_EQUAL ${PACKAGE_VERSION})
   set(PACKAGE_VERSION_EXACT True)
   set(PACKAGE_VERSION_COMPATIBLE True)
 endif()
 
-if(${PACKAGE_FIND_VERSION} VERSION_LESS ${PACKAGE_VERSION})
+if("${PACKAGE_FIND_VERSION}" VERSION_LESS ${PACKAGE_VERSION})
   set(PACKAGE_VERSION_COMPATIBLE True)
 endif()