blockjob: Fix error message for negative speed

The error message for a negative speed uses QERR_INVALID_PARAMETER,
which implies that the 'speed' option doesn't even exist:

    {"error": {"class": "GenericError", "desc": "Invalid parameter 'speed'"}}

Make it use QERR_INVALID_PARAMETER_VALUE instead:

    {"error": {"class": "GenericError", "desc": "Parameter 'speed' expects a non-negative value"}}

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

blockjob.c

@@ -261,7 +261,8 @@ void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
         return;
     }
     if (speed < 0) {
-        error_setg(errp, QERR_INVALID_PARAMETER, "speed");
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "speed",
+                   "a non-negative value");
         return;
     }
 

tests/qemu-iotests/030

@@ -943,7 +943,7 @@ class TestSetSpeed(iotests.QMPTestCase):
         self.assert_no_active_block_jobs()
 
         result = self.vm.qmp('block-stream', device='drive0', speed=-1)
-        self.assert_qmp(result, 'error/desc', "Invalid parameter 'speed'")
+        self.assert_qmp(result, 'error/desc', "Parameter 'speed' expects a non-negative value")
 
         self.assert_no_active_block_jobs()
 
@@ -952,7 +952,7 @@ class TestSetSpeed(iotests.QMPTestCase):
         self.assert_qmp(result, 'return', {})
 
         result = self.vm.qmp('block-job-set-speed', device='drive0', speed=-1)
-        self.assert_qmp(result, 'error/desc', "Invalid parameter 'speed'")
+        self.assert_qmp(result, 'error/desc', "Parameter 'speed' expects a non-negative value")
 
         self.cancel_and_wait(resume=True)