more error-prone issue fix

Change-Id: I49f2cc0459cfddddc6a99e2ebb8ad52d547e2909
diff --git a/utils/misc/pom.xml b/utils/misc/pom.xml
index 653ed4a..1bfc038 100644
--- a/utils/misc/pom.xml
+++ b/utils/misc/pom.xml
@@ -31,7 +31,6 @@
     <description>Miscellaneous ON.Lab utilities</description>
 
     <properties>
-        <metrics.version>3.1.2</metrics.version>
     </properties>
 
     <dependencies>
@@ -77,12 +76,10 @@
         <dependency>
             <groupId>io.dropwizard.metrics</groupId>
             <artifactId>metrics-core</artifactId>
-            <version>${metrics.version}</version>
         </dependency>
         <dependency>
             <groupId>io.dropwizard.metrics</groupId>
             <artifactId>metrics-json</artifactId>
-            <version>${metrics.version}</version>
         </dependency>
         <dependency>
             <groupId>org.apache.felix</groupId>
diff --git a/utils/misc/src/main/java/org/onlab/util/Tools.java b/utils/misc/src/main/java/org/onlab/util/Tools.java
index 0989010..bf9bea0 100644
--- a/utils/misc/src/main/java/org/onlab/util/Tools.java
+++ b/utils/misc/src/main/java/org/onlab/util/Tools.java
@@ -162,7 +162,7 @@
      * @param collection collection to test
      * @return true if null or empty; false otherwise
      */
-    public static boolean isNullOrEmpty(Collection collection) {
+    public static boolean isNullOrEmpty(Collection<?> collection) {
         return collection == null || collection.isEmpty();
     }