fixed: ctrl+c to break will get bagarg when staring observer_cli by rpc

[{erlang,'--',[{error,terminated},"\n"],[]},{observer_cli_lib,parse_integer,1,[{file,"observer_cli_lib.erl"},{line,387}]},{observer_cli,manager,4,[{file,"observer_cli.erl"},{line,101}]},{emqx_ctl,run_command,2,[{file,"emqx_ctl.erl"},{line,104}]},{erpc,execute_call,4,[{file,"erpc.erl"},{line,416}]}]

src/observer_cli_lib.erl

@@ -362,6 +362,9 @@ parse_cmd(ViewOpts, Module, Args) ->
             hide;
         "`\n" ->
             scheduler_usage;
+        %% {error, estale}|{error, terminated}
+        {error, _Reason} ->
+            quit;
         Number ->
             parse_integer(Number)
     end.

src/observer_cli_plugin.erl

@@ -230,6 +230,8 @@ parse_cmd() ->
         "F\n" -> page_down_top_n;
         "q\n" -> quit;
         "\n" -> jump;
+        %% {error, estale}|{error, terminated}
+        {error, _Reason} -> quit;
         Number -> observer_cli_lib:parse_integer(Number)
     end.
 

src/observer_cli_process.erl

@@ -426,6 +426,9 @@ parse_cmd() ->
             home;
         "B\n" ->
             back;
+        %% {error, estale}|{error, terminated}
+        {error, _Reason} ->
+            quit;
         Number ->
             observer_cli_lib:parse_integer(Number)
     end.