Enable UNIT_gz_TEST on Windows (#128)

Signed-off-by: Addisu Z. Taddese <addisu@openrobotics.org>

Author: Addisu Z. Taddese

loader/CMakeLists.txt

@@ -3,7 +3,7 @@
 gz_get_libsources_and_unittests(sources tests)
 
 # Disable gz_TEST if gz-tools is not found
-if (MSVC OR NOT GZ_TOOLS_PROGRAM)
+if (NOT GZ_TOOLS_PROGRAM)
   list(REMOVE_ITEM tests src/gz_TEST.cc)
 endif()