Update plugin-script.asciidoc
Update plugin-script.asciidoc

It is better not to show lang-groovy plugin in the example, as it is not used since elasticsearch 1.4.0
strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test,strapdata/elassandra-test