Fix compiler warnings

src/main/java/org/apache/commons/logging/LogSource.java

@@ -136,7 +136,7 @@ public class LogSource {
      * @param clazz a Class.
      * @return a {@code Log} instance.
      */
-    static public Log getInstance(final Class clazz) {
+    static public Log getInstance(final Class<?> clazz) {
         return getInstance(clazz.getName());
     }
 

src/main/java/org/apache/commons/logging/impl/Log4jApiLogFactory.java

@@ -194,7 +194,7 @@ public final class Log4jApiLogFactory extends LogFactory {
     }
 
     @Override
-    public Log getInstance(final Class clazz) {
+    public Log getInstance(final Class<?> clazz) {
         return getInstance(clazz.getName());
     }
 

src/main/java/org/apache/commons/logging/impl/LogFactoryImpl.java

@@ -823,7 +823,7 @@ public class LogFactoryImpl extends LogFactory {
      *  instance cannot be returned
      */
     @Override
-    public Log getInstance(final Class clazz) throws LogConfigurationException {
+    public Log getInstance(final Class<?> clazz) throws LogConfigurationException {
         return getInstance(clazz.getName());
     }
 

src/main/java/org/apache/commons/logging/impl/Slf4jLogFactory.java

@@ -278,7 +278,7 @@ public final class Slf4jLogFactory extends LogFactory {
     }
 
     @Override
-    public Log getInstance(final Class clazz) throws LogConfigurationException {
+    public Log getInstance(final Class<?> clazz) throws LogConfigurationException {
         return getInstance(clazz.getName());
     }