Add missing about files to source jars

Signed-off-by: Fred Bricon <fbricon@gmail.com>
diff --git a/org.eclipse.m2e.wtp.jpa/build.properties b/org.eclipse.m2e.wtp.jpa/build.properties
index dccddef..638a219 100644
--- a/org.eclipse.m2e.wtp.jpa/build.properties
+++ b/org.eclipse.m2e.wtp.jpa/build.properties
@@ -10,3 +10,7 @@
                about.properties,\
                lifecycle-mapping-metadata.xml,\
                m2e-wtp_icon_32px.png
+src.includes = about.html,\
+               about.ini,\
+               about.mappings,\
+               about.properties