Revert "Update min_sdk_version from SdkSpec to ApiLevel"

Revert submission 2457063

Reason for revert: Broken udc-dev

Reverted changes: /q/submissionid:2457063

Change-Id: Id6349fc1318877044af713c914a0afd437d3d2d5
diff --git a/android/sdk.go b/android/sdk.go
index 63e0bbe..8b23d63 100644
--- a/android/sdk.go
+++ b/android/sdk.go
@@ -25,7 +25,7 @@
 
 // minApiLevelForSdkSnapshot provides access to the min_sdk_version for MinApiLevelForSdkSnapshot
 type minApiLevelForSdkSnapshot interface {
-	MinSdkVersion(ctx EarlyModuleContext) ApiLevel
+	MinSdkVersion(ctx EarlyModuleContext) SdkSpec
 }
 
 // MinApiLevelForSdkSnapshot returns the ApiLevel of the min_sdk_version of the supplied module.
@@ -34,7 +34,7 @@
 func MinApiLevelForSdkSnapshot(ctx EarlyModuleContext, module Module) ApiLevel {
 	minApiLevel := NoneApiLevel
 	if m, ok := module.(minApiLevelForSdkSnapshot); ok {
-		minApiLevel = m.MinSdkVersion(ctx)
+		minApiLevel = m.MinSdkVersion(ctx).ApiLevel
 	}
 	if minApiLevel == NoneApiLevel {
 		// The default min API level is 1.