fix plurality when generating email for VOTE

[rabbah]

when the num of components is 1 the email generator will do this:

This is a call to vote on releasing version 0.11.0-incubating release
candidate rc2 of the following 1 project modules with artifacts
built from the Git repositories and commit IDs listed below.

note that modules is plural, the message should be:

This is a call to vote on releasing version 0.11.0-incubating release
candidate rc2 of the following project module with artifacts
built from the Git repositories and commit IDs listed below.