set willDeleteBackupsOnOfferingRemoval to false for dummy and veeam. Disallow create new instance from networker backup.

Author: abh1sar

plugins/backup/dummy/src/main/java/org/apache/cloudstack/backup/DummyBackupProvider.java

@@ -110,7 +110,7 @@ public boolean removeVMFromBackupOffering(VirtualMachine vm) {
 
     @Override
     public boolean willDeleteBackupsOnOfferingRemoval() {
-        return true;
+        return false;
     }
 
     @Override

plugins/backup/veeam/src/main/java/org/apache/cloudstack/backup/VeeamBackupProvider.java

@@ -221,7 +221,7 @@ public boolean removeVMFromBackupOffering(final VirtualMachine vm) {
 
     @Override
     public boolean willDeleteBackupsOnOfferingRemoval() {
-        return true;
+        return false;
     }
 
     @Override

server/src/main/java/org/apache/cloudstack/backup/BackupManagerImpl.java

@@ -896,6 +896,9 @@ public boolean restoreBackupToVM(final Long backupId, final Long vmId) throws Re
             String errorMessage = "Failed to find backup offering of the VM backup.";
             throw new CloudRuntimeException("Failed to find backup offering of the VM backup.");
         }
+        if ("networker".equals(offering.getProvider())) {
+            throw new CloudRuntimeException("Create instance from VM is not supported for Networker Backup plugin.");
+        }
 
         String backupDetailsInMessage = ReflectionToStringBuilderUtils.reflectOnlySelectedFields(backup, "uuid", "externalId", "newVMId", "type", "status", "date");
         try {