httpcaddyfile: Don't allow i to go below zero

caddyconfig/httpcaddyfile/tlsapp.go

@@ -491,13 +491,14 @@ func consolidateAutomationPolicies(aps []*caddytls.AutomationPolicy) []*caddytls
 	}
 
 	// remove or combine duplicate policies
+outer:
 	for i := 0; i < len(aps); i++ {
 		// compare only with next policies; we sorted by specificity so we must not delete earlier policies
 		for j := i + 1; j < len(aps); j++ {
 			// if they're exactly equal in every way, just keep one of them
 			if reflect.DeepEqual(aps[i], aps[j]) {
 				aps = append(aps[:j], aps[j+1:]...)
-				i--
+				j--
 				break
 			}
 
@@ -524,6 +525,7 @@ func consolidateAutomationPolicies(aps []*caddytls.AutomationPolicy) []*caddytls
 					if automationPolicyShadows(i, aps) >= j {
 						aps = append(aps[:i], aps[i+1:]...)
 						i--
+						continue outer
 					}
 				} else {
 					// avoid repeated subjects