ProjectExplorer: Do not reject user file on target absence

Use-case:
pro.user has 5 targets, while pro.shared has 6.

It is better to have only 5 targets than not opening the project at all.

Change-Id: Ic169a2180aafd0b1ed60a7f6d8903b47e7f1c34e
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/plugins/projectexplorer/project.cpp

@@ -386,7 +386,7 @@ bool Project::fromMap(const QVariantMap &map)
         const QString key(QString::fromLatin1(TARGET_KEY_PREFIX) + QString::number(i));
         if (!map.contains(key)) {
             qWarning() << key << "was not found in data.";
-            return false;
+            continue;
         }
         QVariantMap targetMap = map.value(key).toMap();