fileutils: revert the A+C inclusion, noisy and probably useless

But keep the multiple file copy, as sometimes both LICENSE
and COPYING are present.
diff --git a/fileutils/fileutils.go b/fileutils/fileutils.go
index 875f790..2a36a1d 100644
--- a/fileutils/fileutils.go
+++ b/fileutils/fileutils.go
@@ -24,7 +24,6 @@
 
 var licenseFiles = []string{
 	"LICENSE", "LICENCE", "UNLICENSE", "COPYING", "COPYRIGHT",
-	"AUTHORS", "CONTRIBUTORS",
 }
 
 // Copypath copies the contents of src to dst, excluding any file that is not