Tune how to get the size of SVG images. Ref https://github.com/GNS3/gns3-gui/issues/2674.

* Default for missing height/width is "100%" as defined in the SVG specification
* Better error message, if viewBox attribute is missing
* Removal of "%" in percent more fault tolerant by using rstrip("%")

(cherry picked from commit e3757a8955)

gns3server/handlers/api/controller/symbol_handler.py

@@ -60,7 +60,7 @@ class SymbolHandler:
         r"/symbols/{symbol_id:.+}/raw",
         description="Write the symbol file",
         status_codes={
-            200: "Symbol returned"
+            200: "Symbol written"
         },
         raw=True)
     def upload(request, response):
@@ -78,6 +78,7 @@ class SymbolHandler:
                     f.write(chunk)
         except (UnicodeEncodeError, OSError) as e:
             raise aiohttp.web.HTTPConflict(text="Could not write symbol file '{}': {}".format(path, e))
+
         # Reset the symbol list
         controller.symbols.list()
         response.set_status(204)