Revert "rustc-1.72.0 Build 10752340"

Revert submission 2736851-rust-1.72

Reason for revert: Breaks Mac builds

Change-Id: I94a30e61f9f717ad135fbef7ec7241730f583110
diff --git a/rust/config/global.go b/rust/config/global.go
index c976617..4bd495d 100644
--- a/rust/config/global.go
+++ b/rust/config/global.go
@@ -25,7 +25,7 @@
 	pctx         = android.NewPackageContext("android/soong/rust/config")
 	exportedVars = android.NewExportedVariables(pctx)
 
-	RustDefaultVersion = "1.72.0"
+	RustDefaultVersion = "1.71.0"
 	RustDefaultBase    = "prebuilts/rust/"
 	DefaultEdition     = "2021"
 	Stdlibs            = []string{