rename archival/libunarchive -> archival/libarchive; move bz/ into it

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/archival/rpm.c b/archival/rpm.c
index 7b316a5..380226f 100644
--- a/archival/rpm.c
+++ b/archival/rpm.c
@@ -8,7 +8,7 @@
  */
 
 #include "libbb.h"
-#include "unarchive.h"
+#include "archive.h"
 #include "rpm.h"
 
 #define RPM_CHAR_TYPE           1