Chemistry is a unique, but often difficult thing to explain — when something works, it just works. I guess no explanation is really neeeded. Steel Magnolia has red-hot chemistry as a country music duo. When Meghan Linsey and Joshua Scott Jones were competing against other pairs on season two of the CMT program “Can You Duet,” the spark between this real-life couple leapt off the television screen. What was apparent to TV viewers must have been especially obvious to record exec Scott Borchetta, who served as a judge on the show and whose Big Machine Records label ultimately signed the winning duo to a deal….