Upgrade rust-installer

brson · nikomatsakis · commit 72ff933ebf56 · 2015-01-03T06:00:11.000-05:00
This fixes a mostly harmless syntax error in the install script.
diff --git a/src/rust-installer b/src/rust-installer
@@ -1 +1 @@
-Subproject commit 3a37981744a5af2433fed551f742465c78c9af7f
+Subproject commit 48395771f0b0b5cbd435245dc02dc50822685eef
