rust: Fix exported MinSdkVersion

The exported rust.MinSdkVersion always returns an empty string. Instead
it should return the Min_sdk_version property like rust.minSdkVersion.

This CL renames minSdkVersion to MinSdkVersion so the exported function
has the correct behavior.

Bug: 211858959
Test: m
Change-Id: I4fecfba711c0d3d7a22f4fdf7684924a9457b464
Merged-In: I4fecfba711c0d3d7a22f4fdf7684924a9457b464
diff --git a/rust/rust.go b/rust/rust.go
index 778000d..cba92c3 100644
--- a/rust/rust.go
+++ b/rust/rust.go
@@ -366,10 +366,6 @@
 	return ""
 }
 
-func (mod *Module) MinSdkVersion() string {
-	return ""
-}
-
 func (mod *Module) AlwaysSdk() bool {
 	return false
 }
@@ -1497,15 +1493,13 @@
 
 var _ android.ApexModule = (*Module)(nil)
 
-func (mod *Module) minSdkVersion() string {
+func (mod *Module) MinSdkVersion() string {
 	return String(mod.Properties.Min_sdk_version)
 }
 
-var _ android.ApexModule = (*Module)(nil)
-
 // Implements android.ApexModule
 func (mod *Module) ShouldSupportSdkVersion(ctx android.BaseModuleContext, sdkVersion android.ApiLevel) error {
-	minSdkVersion := mod.minSdkVersion()
+	minSdkVersion := mod.MinSdkVersion()
 	if minSdkVersion == "apex_inherit" {
 		return nil
 	}