Remove unnecessary assignment in PropertiesBeanDefinitionReader

Closes gh-24804

spring-beans/src/main/java/org/springframework/beans/factory/support/PropertiesBeanDefinitionReader.java

@@ -368,7 +368,7 @@ public class PropertiesBeanDefinitionReader extends AbstractBeanDefinitionReader
 				// Key is of form: prefix<name>.property
 				String nameAndProperty = keyString.substring(prefix.length());
 				// Find dot before property name, ignoring dots in property keys.
-				int sepIdx = -1;
+				int sepIdx ;
 				int propKeyIdx = nameAndProperty.indexOf(PropertyAccessor.PROPERTY_KEY_PREFIX);
 				if (propKeyIdx != -1) {
 					sepIdx = nameAndProperty.lastIndexOf(SEPARATOR, propKeyIdx);