Fix add existing IOS not working

Fix https://github.com/GNS3/gns3-gui/issues/775

gns3server/modules/dynamips/__init__.py

@@ -733,5 +733,5 @@ class Dynamips(BaseManager):
                     continue
                 # valid IOS images must start with the ELF magic number, be 32-bit, big endian and have an ELF version of 1
                 if elf_header_start == b'\x7fELF\x01\x02\x01':
-                    images.append({"filename": filename})
+                    images.append({"filename": filename, "path": path})
         return images

gns3server/schemas/vm.py

@@ -26,13 +26,16 @@ VM_LIST_IMAGES_SCHEMA = {
             "properties": {
                 "filename": {
                     "description": "Image filename",
-                    "type": "string"
+                    "type": "string",
+                    "minLength": 1
                 },
                 "path": {
                     "description": "Image path",
-                    "type": "string"
+                    "type": "string",
+                    "minLength": 1
                 }
             },
+            "required": ["filename", "path"],
             "additionalProperties": False
         }
     ],