error: Don't append a newline when printing the error hint

Since commit 50b7b000, we have error_append_hint() to conveniently
accumulate Error member @hint.  error_report_err() prints it with a
newline appended.  Consequently, users of error_append_hint() need to
know whether theirs is the final line of the hint to decide whether it
needs a newline.  Not a nice interface.

Change error_report_err() to print just the hint, and the (still few)
users of error_append_hint() to add the required newline.

Cc: Eric Blake <eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <1450370121-5768-7-git-send-email-armbru@redhat.com>

qdev-monitor.c

@@ -304,6 +304,7 @@ static void qbus_list_bus(DeviceState *dev, Error **errp)
         error_append_hint(errp, "%s\"%s\"", sep, child->name);
         sep = ", ";
     }
+    error_append_hint(errp, "\n");
 }
 
 static void qbus_list_dev(BusState *bus, Error **errp)
@@ -321,6 +322,7 @@ static void qbus_list_dev(BusState *bus, Error **errp)
         }
         sep = ", ";
     }
+    error_append_hint(errp, "\n");
 }
 
 static BusState *qbus_find_bus(DeviceState *dev, char *elem)

util/error.c

@@ -204,7 +204,7 @@ void error_report_err(Error *err)
 {
     error_report("%s", error_get_pretty(err));
     if (err->hint) {
-        error_printf_unless_qmp("%s\n", err->hint->str);
+        error_printf_unless_qmp("%s", err->hint->str);
     }
     error_free(err);
 }

util/qemu-option.c

@@ -206,7 +206,7 @@ void parse_option_size(const char *name, const char *value,
         default:
             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, name, "a size");
             error_append_hint(errp, "You may use k, M, G or T suffixes for "
-                    "kilobytes, megabytes, gigabytes and terabytes.");
+                    "kilobytes, megabytes, gigabytes and terabytes.\n");
             return;
         }
     } else {
@@ -647,7 +647,7 @@ QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id,
             error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "id",
                        "an identifier");
             error_append_hint(errp, "Identifiers consist of letters, digits, "
-                              "'-', '.', '_', starting with a letter.");
+                              "'-', '.', '_', starting with a letter.\n");
             return NULL;
         }
         opts = qemu_opts_find(list, id);