Do not reset annotation value in case setting an invalid string fails

Issue-Ref: 3696
Issue-Url: https://af3-developer.fortiss.org/issues/3696



Signed-off-by: Simon Barner <barner@fortiss.org>

org.fortiss.tooling.base/src/org/fortiss/tooling/base/annotation/valueprovider/.ratings

 AnnotationInstSpec.java b4f2ed47a8984e751e04049de5bdb3cad2c0a933 GREEN
 DerivedAnnotationValueProviderBase.java 15da44b7b92b7fd351aa48422ff5957a2ce34e35 GREEN
 EStructuralFeatureDescriptor.java 2e14df3830d854bc1693382727b2033b23d0051c GREEN
-EStructuralFeatureValueProviderBase.java 7e3f41a7e5c22fda63058fb5cd1c8036df0e8a3f GREEN
+EStructuralFeatureValueProviderBase.java 71c418486bc6c46bc468e18c92b21f6b537706db YELLOW
 IAnnotationValueProvider.java d093cb522e7c484420331f0c77690bebe7e131b4 GREEN
 ValueProviderBase.java e4e866840845346ec99a4304048f5327c4890996 GREEN

org.fortiss.tooling.base/src/org/fortiss/tooling/base/annotation/valueprovider/EStructuralFeatureValueProviderBase.java

@@ -163,7 +163,7 @@ public abstract class EStructuralFeatureValueProviderBase<T extends IAnnotatedSp
 				specification.eSet(structuralFeature,
 						eFactory.createFromString(eAttributeType, value));
 			} catch(Exception e) {
-				specification.eSet(structuralFeature, null);
+				// Keep previous value
 			}
 		} else {
 			throw new Exception(