[gimp] Issue #2848: some sentences have no translation.

[Jehan <jehanp src gnome org>]

commit f508e24f0c0a53f5c99b2aa4784d25d213eaa686
Author: Jehan <jehan girinstud io>
Date:   Thu Jan 24 16:14:46 2019 +0100

    Issue #2848: some sentences have no translation.

 app/operations/gimpoperationsemiflatten.c    | 4 ++--
 app/operations/gimpoperationthresholdalpha.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/app/operations/gimpoperationsemiflatten.c b/app/operations/gimpoperationsemiflatten.c
index ce0c630709..1352f02bb2 100644
--- a/app/operations/gimpoperationsemiflatten.c
+++ b/app/operations/gimpoperationsemiflatten.c
@@ -92,8 +92,8 @@ gimp_operation_semi_flatten_class_init (GimpOperationSemiFlattenClass *klass)
 
   g_object_class_install_property (object_class, PROP_COLOR,
                                    gimp_param_spec_rgb ("color",
-                                                        "Color",
-                                                        "The color",
+                                                        _("Color"),
+                                                        _("The color"),
                                                         FALSE, &white,
                                                         G_PARAM_READWRITE |
                                                         G_PARAM_CONSTRUCT));
diff --git a/app/operations/gimpoperationthresholdalpha.c b/app/operations/gimpoperationthresholdalpha.c
index 2a3edeffe6..94cbaf51a0 100644
--- a/app/operations/gimpoperationthresholdalpha.c
+++ b/app/operations/gimpoperationthresholdalpha.c
@@ -87,8 +87,8 @@ gimp_operation_threshold_alpha_class_init (GimpOperationThresholdAlphaClass *kla
 
   g_object_class_install_property (object_class, PROP_VALUE,
                                    g_param_spec_double ("value",
-                                                        "Value",
-                                                        "The alpha value",
+                                                        _("Value"),
+                                                        _("The alpha value"),
                                                         0.0, 1.0, 0.5,
                                                         G_PARAM_READWRITE |
                                                         G_PARAM_CONSTRUCT));