Rename COPYRIGHT to COPYING

The standard name people have adopted is "COPYING" rather than
"COPYRIGHT".  Use that as a lot of license scanning tools look for it.

* COPYRIGHT: Rename to ...
* COPYING: ... this.
* Makefile.am (EXTRA_DIST): Rename COPYRIGHT to COPYING.
* README: Likewise.
* strace.spec (%files): Likewise.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/Makefile.am b/Makefile.am
index 99d9eaf..f3ae0ba 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -50,7 +50,7 @@
 EXTRA_DIST =				\
 	$(man_MANS)			\
 	.version			\
-	COPYRIGHT			\
+	COPYING				\
 	CREDITS				\
 	ChangeLog			\
 	ChangeLog-CVS			\