What does bubble reputation mean?

Shakespeare uses the phrase in Jaques's "All the world's a stage" speech (2.7.138-165) in As You Like It. According to dictionary.net, one of the definitions (now obsolete) for bubble is: "A person deceived by an empty project." Since the soldier to whom the bard is referring is said to be "Seeking the bubble reputation / Even in the canon's mouth," bubble reputation could mean fame for participating in a project one believe's to be meaningful but is, in fact, not worthwhile. Shakespeare seems to be referring to a soldier's desire for renown based on his efforts in battle, even to the extent that he would sacrifice his life, but that this effort is empty because the war he is fighting is not noble or even necessary.

Alternate View: A bubble is fragile and easily destroyed as is a mans reputation. The cannon's mouth is not that of his own cannon but the enemy's. He seeks that which is most fragile at a dangerous place, and therefore values his reputation highly, highly enough to risk his life for it. It is not wise to put 21st century values on 16th century words, and doubly unwise to put 21st Century thoughts and attitudes into 16th Century minds, the fit is poor at best.