Remove unused variable in lib/bio/appl/blast/report

This commit removes below interpreter warning.

* warning: assigned but unused variable
Remove unused variable in lib/bio/appl/meme/mast/report

This commit removes below interpreter warning.

* warning: assigned but unused variable
suppress warning "assigned but unused variable"
Remove unused variable in lib/bio/appl/paml/common

This commit removes below interpreter warning.

* warning: assigned but unused variable
Refactoring to suppress warnings "assigned but unused variable"
add a dummy line to suppress "warning: assigned but unused variable"
Rename unused variable in lib/bio/db/gff.rb

This commit removes below interpreter warning.

* warning: assigned but unused variable
Remove unused variable in lib/bio/db/go.rb

This commit removes below interpreter warning.

* warning: assigned but unused variable
Rename unused variable in lib/bio/db/kegg/reaction.rb

This commit removes below interpreter warning.

* warning: assigned but unused variable
Refactoring to suppress warnings "assigned but unused variable"
Remove unused variable in lib/bio/db/transfac.rb

This commit removes below interpreter warning.

* warning: assigned but unused variable
Refactoring to suppress "warning: assigned but unused variable"
Rename unused variable in lib/bio/tree.rb

This commit removes below interpreter warning.

* warning: assigned but unused variable
Remove unused variable in lib/bio/util/contingency_table.rb

This commit removes below interpreter warning.

* warning: assigned but unused variable