Fix cursor line overwriting in prepare_registration

When I issue a `prepare_registration` command the cursor gets positioned
at the beginning of the line instead of the end of the line, so typing
things in results in overwriting the text that I was asked.

E.g.:

```
Current staking requirement: 15000.000000000 oxen
yill the operator contribute the entire stake? (Y/Yes/N/No/C/Cancel):
`-- the y I typed replaced the "W"
```
or:
```
Enter the oxen address for the solo staker (B/Back/C/Cancel):
```
and because the cursor is positioned at the beginning, my address
overwrites the prompt as I type/paste it:
```
L6JasonXTGoxen address for the solo staker (B/Back/C/Cancel):
```

This is caused because we were suspending the readline buffer *after*
printing things out, and something (perhaps local config, or perhaps an
update to libreadline) repositions to cursor at column 0.

This commit suspends the readline handler *before* we print the message,
which makes it sane again:
```
Enter the oxen address for the solo staker (B/Back/C/Cancel): L6JasonXTG
```

src/daemon/rpc_command_executor.cpp

@@ -63,9 +63,9 @@ namespace {
 
   std::string input_line(std::string const &prompt)
   {
+    rdln::suspend_readline pause_readline;
     std::cout << prompt << std::flush;
     std::string result;
-    rdln::suspend_readline pause_readline;
     std::cin >> result;
 
     return result;