make: Define dummy target for scripts/Makefile.version

At moment built-in .SUFFIXES variable is not cleaned
which slows down the building procedure. Add a dummy
rule thus the make won't try to lookup rules for
scripts/Makefile.version (this happens when last
resort rule is used).

Note that this is rather a stub for future convenience
which doesn't affect much current build procedure.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

scripts/Makefile.version

@@ -21,3 +21,10 @@ $(VERSION_HEADER): scripts/Makefile.version
 	$(Q) echo "#define CRIU_VERSION_MAJOR " $(VERSION_MAJOR)	>> $(VERSION_HEADER)
 	$(Q) echo "#define CRIU_VERSION_MINOR " $(VERSION_MINOR)	>> $(VERSION_HEADER)
 	$(Q) echo "#endif /* __CR_VERSION_H__ */"			>> $(VERSION_HEADER)
+
+##
+## In case if someone add last resort rule
+## together with .SUFFIXES not cleaned, this
+## will slow down the build procedure
+scripts/Makefile.version::
+	@echo > /dev/null