liblzma: Remove incorrect #ifdef from range_common.h.

In most cases it was harmless but it could affect some
custom build systems.

Thanks to Pippijn van Steenhoven.
diff --git a/src/liblzma/rangecoder/range_common.h b/src/liblzma/rangecoder/range_common.h
index 0e64241..2c74dc1 100644
--- a/src/liblzma/rangecoder/range_common.h
+++ b/src/liblzma/rangecoder/range_common.h
@@ -14,9 +14,7 @@
 #ifndef LZMA_RANGE_COMMON_H
 #define LZMA_RANGE_COMMON_H
 
-#ifdef HAVE_CONFIG_H
-#	include "common.h"
-#endif
+#include "common.h"
 
 
 ///////////////