pom.xml: Depend on hamcrest, not on hamcrest-library

hamcrest-library is a deprecated dependency, as indicated by
hamcrest-library-2.1.pom.

Author: proski

pom.xml

@@ -93,7 +93,7 @@
     </dependency>
     <dependency>
       <groupId>org.hamcrest</groupId>
-      <artifactId>hamcrest-library</artifactId>
+      <artifactId>hamcrest</artifactId>
       <version>2.1</version>
       <scope>test</scope>
     </dependency>