Best Buy Co. Inc. has two floods to deal with this week: The actual one, which has closed dozens of stores in the Houston area, and a tide of online criticism over a photo seeming to show a Houston-area Best Buy store selling packs of bottled water at a big markup. The photo, showing 24-packs of water bottles priced at $42.96 (and a smaller option at $29.98) went viral on Tuesday as part of a story on the website Gritpost about reports of price-gouging by Houston-area retailers. One Houston resident…