Make the test harder by always having a space in the include dirs

The commit message for the previous commit was wrong, it should
have been: fix the test by using $(shell ...) syntax instead
of backticks in the Makefile.
With backticks I couldn't get the quoting right.
Printing -I"/some/path with space" did not work, the compiler
complained that there is not file "with". Also backslashes in
different numbers did not make it work.

Alex

Tests/FindPackageModeMakefileTest/FindFoo.cmake.in

@@ -3,6 +3,7 @@ find_library(FOO_LIBRARY NAMES foo HINTS "@CMAKE_CURRENT_BINARY_DIR@" )
 find_path(FOO_INCLUDE_DIR NAMES foo.h HINTS "@CMAKE_CURRENT_SOURCE_DIR@" )
 
 set(FOO_LIBRARIES ${FOO_LIBRARY})
+set(FOO_INCLUDE_DIRS "${FOO_INCLUDE_DIR}"  "/some/path/with a space/include" )
 
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(Foo  DEFAULT_MSG  FOO_LIBRARY FOO_INCLUDE_DIR )