org.texi and orgguide.texi: Hyphen and dash fixes.

See revno 111060 by Paul Eggert from the emacs-24 bzr branch.

doc/org.texi

@@ -263,7 +263,7 @@
 @copying
 This manual is for Org version @value{VERSION}.
 
-Copyright @copyright{} 2004-2012 Free Software Foundation, Inc.
+Copyright @copyright{} 2004--2012 Free Software Foundation, Inc.
 
 @quotation
 Permission is granted to copy, distribute and/or modify this document

doc/orgguide.texi

@@ -39,7 +39,7 @@
 @end macro
 @copying
 
-Copyright @copyright{} 2010-2012 Free Software Foundation
+Copyright @copyright{} 2010--2012 Free Software Foundation
 
 @quotation
 Permission is granted to copy, distribute and/or modify this document