Return relative path for dynamips images

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

gns3server/modules/dynamips/__init__.py

@@ -733,5 +733,6 @@ 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':
+                    path = os.path.relpath(path, image_dir)
                     images.append({"filename": filename, "path": path})
         return images

tests/handlers/api/test_dynamips.py

@@ -156,7 +156,7 @@ def test_vms(server, tmpdir, fake_dynamips, fake_file):
     with patch("gns3server.modules.Dynamips.get_images_directory", return_value=str(tmpdir), example=True):
         response = server.get("/dynamips/vms")
     assert response.status == 200
-    assert response.json == [{"filename": "7200.bin", "path": str(tmpdir / "7200.bin")}]
+    assert response.json == [{"filename": "7200.bin", "path": "7200.bin"}]
 
 
 def test_upload_vm(server, tmpdir):