Fix typo in installer.go

Test: builds
Change-Id: I51364616e2a16f932d34ef33565d04a00d8f4ca5
diff --git a/cc/installer.go b/cc/installer.go
index 2522610..e2c0e7b 100644
--- a/cc/installer.go
+++ b/cc/installer.go
@@ -31,7 +31,7 @@
 	Install_in_root *bool `android:"arch_variant"`
 
 	// Install output directly in {partition}/xbin
-	Install_in_xbin *bool `android:"arch_vvariant"`
+	Install_in_xbin *bool `android:"arch_variant"`
 }
 
 type installLocation int