Bug 453379 - Make sure to precompile jsps with the same Jetty version

Use jetty-version property from eclipse-platform-parent pom so jsp files
are precompiled with the same Jetty version shipped to minimize possible
incompatibilities. A change is groupId is needed for version 9.x of
jetty-jspc-maven-plugin.

Change-Id: Icbc593dcd9600ffe157f977f0cd8c74aebedfc36
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>
diff --git a/org.eclipse.help.webapp/pom.xml b/org.eclipse.help.webapp/pom.xml
index 517ee79..9d9ed47 100644
--- a/org.eclipse.help.webapp/pom.xml
+++ b/org.eclipse.help.webapp/pom.xml
@@ -23,9 +23,9 @@
   <build>
     <plugins>
       <plugin>
-        <groupId>org.mortbay.jetty</groupId>
+        <groupId>org.eclipse.jetty</groupId>
         <artifactId>jetty-jspc-maven-plugin</artifactId>
-        <version>8.1.8.v20121106</version>
+        <version>${jetty-version}</version>
         <executions>
           <execution>
             <id>jspc</id>