ProjectExplorer: Replace the fromMap error return value

... by some out-of-band mechanism, keeping previous functionality.

The driving reason is to get the same fromMap signature as in the
AspectContainer base, however, the whole mechanism seems rather useless:
There are only a few places that actually ever could report errors,
in those places "moving on" looks ok, too, and these few places
are not conceptually different than a lot others.

Removal of this (new) mechanism is left for later.

Change-Id: Ibe7a0456bc3b84a84e942231f14446e783372d76
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp

@@ -1562,16 +1562,6 @@ CMakeBuildConfiguration::~CMakeBuildConfiguration()
     delete m_buildSystem;
 }
 
-void CMakeBuildConfiguration::toMap(QVariantMap &map) const
-{
-    BuildConfiguration::toMap(map);
-}
-
-bool CMakeBuildConfiguration::fromMap(const QVariantMap &map)
-{
-    return BuildConfiguration::fromMap(map);
-}
-
 FilePath CMakeBuildConfiguration::shadowBuildDirectory(const FilePath &projectFilePath,
                                                        const Kit *k,
                                                        const QString &bcName,

src/plugins/cmakeprojectmanager/cmakebuildconfiguration.h

@@ -90,11 +90,7 @@ signals:
     void signingFlagsChanged();
     void configureEnvironmentChanged();
 
-protected:
-    bool fromMap(const QVariantMap &map) override;
-
 private:
-    void toMap(QVariantMap &map) const override;
     BuildType buildType() const override;
 
     ProjectExplorer::NamedWidget *createConfigWidget() override;

src/plugins/cmakeprojectmanager/cmakebuildstep.cpp

@@ -281,7 +281,7 @@ void CMakeBuildStep::toMap(QVariantMap &map) const
     map.insert(QLatin1String(BUILD_PRESET_KEY), m_buildPreset);
 }
 
-bool CMakeBuildStep::fromMap(const QVariantMap &map)
+void CMakeBuildStep::fromMap(const QVariantMap &map)
 {
     setBuildTargets(map.value(BUILD_TARGETS_KEY).toStringList());
 
@@ -294,7 +294,7 @@ bool CMakeBuildStep::fromMap(const QVariantMap &map)
 
     m_buildPreset = map.value(QLatin1String(BUILD_PRESET_KEY)).toString();
 
-    return BuildStep::fromMap(map);
+    BuildStep::fromMap(map);
 }
 
 bool CMakeBuildStep::init()

src/plugins/cmakeprojectmanager/cmakebuildstep.h

@@ -83,7 +83,7 @@ signals:
 private:
     Utils::CommandLine cmakeCommand() const;
 
-    bool fromMap(const QVariantMap &map) override;
+    void fromMap(const QVariantMap &map) override;
 
     bool init() override;
     void setupOutputFormatter(Utils::OutputFormatter *formatter) override;