tree-wide: standardize on $(PACKAGE_VERSION) for the version string

We defined both $(VERSION) and $(PACKAGE_VERSION) with the same contents.
$(PACKAGE_VERSION) is slightly more descriptive, so settle on that, and
drop the other define.

src/test/test-libudev.c

@@ -392,7 +392,7 @@ int main(int argc, char *argv[]) {
                         return EXIT_SUCCESS;
 
                 case 'V':
-                        printf("%s\n", VERSION);
+                        printf("%s\n", PACKAGE_VERSION);
                         return EXIT_SUCCESS;
 
                 case 'm':

src/test/test-udev.c

@@ -88,7 +88,7 @@ int main(int argc, char *argv[]) {
         if (udev == NULL)
                 return EXIT_FAILURE;
 
-        log_debug("version %s", VERSION);
+        log_debug("version %s", PACKAGE_VERSION);
         mac_selinux_init();
 
         action = argv[1];