distcheck: Include .version to fix build on newer versions

echo 1.3.0.66-35f9 > ../../.version-t && mv ../../.version-t ../../.version
/bin/bash: ../../.version-t: Permission denied
Makefile:786: recipe for target '../../.version' failed
diff --git a/Makefile.am b/Makefile.am
index 663de61..eb588c1 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -8,3 +8,5 @@
 	echo $(VERSION) > $@-t && mv $@-t $@
 dist-hook:
 	echo $(VERSION) > $(distdir)/.tarball-version
+
+EXTRA_DIST = .version