Silencing error output in the "Listing Versions" teardown script.

test/fast/Listing versions/teardown

@@ -1,12 +1,12 @@
-rmdir ../../../v0.0.1
-rmdir ../../../v0.0.3
-rmdir ../../../v0.0.9
-rmdir ../../../v0.1.2
-rmdir ../../../v0.1.3
-rmdir ../../../v0.2.3
-rmdir ../../../v0.3.1
-rmdir ../../../v0.3.3
-rmdir ../../../v0.3.9
-rmdir ../../../versions
-unalias nvm_has_system_node
+rmdir ../../../v0.0.1 >/dev/null 2>&1
+rmdir ../../../v0.0.3 >/dev/null 2>&1
+rmdir ../../../v0.0.9 >/dev/null 2>&1
+rmdir ../../../v0.1.2 >/dev/null 2>&1
+rmdir ../../../v0.1.3 >/dev/null 2>&1
+rmdir ../../../v0.2.3 >/dev/null 2>&1
+rmdir ../../../v0.3.1 >/dev/null 2>&1
+rmdir ../../../v0.3.3 >/dev/null 2>&1
+rmdir ../../../v0.3.9 >/dev/null 2>&1
+rmdir ../../../versions >/dev/null 2>&1
+unalias nvm_has_system_node >/dev/null 2>&1