tests: fix console_data if not under screen

In commit 059aa62 we started gathering
console_data if a test failed. However console_data errors if we were
not using screen in the first place.

Fixes: 059aa62

Signed-off-by: Pablo Barbáchano <[email protected]>

Author: pb8o

tests/framework/microvm.py

@@ -411,7 +411,10 @@ def console_data(self):
         """Return the output of microVM's console"""
         if self.screen_log is None:
             return None
-        return Path(self.screen_log).read_text(encoding="utf-8")
+        file = Path(self.screen_log)
+        if not file.exists():
+            return None
+        return file.read_text(encoding="utf-8")
 
     @property
     def state(self):