m1n1.shell: carry on if saving history fails

This shouldn't crash the shell — it's enough to warn about it and
carry on.

Signed-off-by: Alyssa Ross <hi@alyssa.is>

Author: alyssais

proxyclient/m1n1/shell.py

@@ -30,7 +30,10 @@ def init_history(self, histfile):
 
     def save_history(self):
         readline.set_history_length(10000)
-        readline.write_history_file(self.histfile)
+        try:
+            readline.write_history_file(self.histfile)
+        except OSError as e:
+            print(f"Failed writing history to {self.histfile}: {e}", file=sys.stderr)
 
     def showtraceback(self):
         type, value, tb = sys.exc_info()