Fixed a typo in our pom

The tag should have been relativePath not relative
diff --git a/org.eclipse.equinox.p2.releng/org.eclipse.equinox.p2-parent/pom.xml b/org.eclipse.equinox.p2.releng/org.eclipse.equinox.p2-parent/pom.xml
index 9dbebf8..42ac5e5 100644
--- a/org.eclipse.equinox.p2.releng/org.eclipse.equinox.p2-parent/pom.xml
+++ b/org.eclipse.equinox.p2.releng/org.eclipse.equinox.p2-parent/pom.xml
@@ -17,7 +17,7 @@
   <parent>
     <groupId>org.eclipse</groupId>
     <artifactId>eclipse-platform-parent</artifactId>
-	<relative>../../eclipse-platform-parent</relative>
+    <relativePath>../../eclipse-platform-parent</relativePath>
     <version>1.0.0-SNAPSHOT</version>
   </parent>