Change ant dependencies in pom to provided

The compile dependency on ant 1.6.5 libraries means that these are dragged in when xharness is invoked via the maven antrun plugin. This may cuase complications when antrun is configured to use a different ant version, e.g. ant 1.7.x

As a workaround, the ant and ant-junit dependencies can be excluded from the xharness dependency:

<dependency>
<groupId>org.codehaus.xharness</groupId>
<artifactId>xharness</artifactId>
<version>1.0-beta3</version>
<exclusions>
<exclusion>
<groupId>ant</groupId>
<artifactId>ant</artifactId>
</exclusion>
<exclusion>
<groupId>ant</groupId>
<artifactId>ant-junit</artifactId>
</exclusion>
</exclusions>
</dependency>