core: Ignore maven-ear-plugin in Eclipse

Eclipse doesn't have support for most of the parameters of the
maven-ear-plugin, so in order to import the project without errors we
need to ignore the execution of the generate-application-xml goal.

Change-Id: I196ae0fd10615e8576a6fa3abc3dfcbc2a530e86
Signed-off-by: Juan Hernandez <juan.hernandez@redhat.com>