Allow M23 "File opened" response with no filename

(cherry-picked from ba4b7c0)

src/octoprint/settings.py

@@ -293,7 +293,7 @@ default_settings = {
 			"okWithLinenumber": False,
 			"numExtruders": 1,
 			"includeCurrentToolInTemps": True,
-			"includeFilenameOnOpened": True,
+			"includeFilenameInOpened": True,
 			"movementSpeed": {
 				"x": 6000,
 				"y": 6000,

src/octoprint/util/comm.py

@@ -1120,12 +1120,16 @@ class MachineCom(object):
 				elif 'File opened' in line and not self._ignore_select:
 					# answer to M23, at least on Marlin, Repetier and Sprinter: "File opened:%s Size:%d"
 					match = regex_sdFileOpened.search(line)
+					if match:
+						name = match.group("name")
+						size = int(match.group("size"))
+					else:
+						name = "Unknown"
+						size = 0
 					if self._sdFileToSelect:
 						name = self._sdFileToSelect
 						self._sdFileToSelect = None
-					else:
-						name = match.group("name")
-					self._currentFile = PrintingSdFileInformation(name, int(match.group("size")))
+					self._currentFile = PrintingSdFileInformation(name, size)
 				elif 'File selected' in line:
 					if self._ignore_select:
 						self._ignore_select = False