fix compile warning: catch all Throwables

[ingallsj]

Type of change: paying off technical debt

Impact: no functional change

What was changed
fix compile warnings:

[warn] /barstools/mdf/scalalib/src/main/scala/SRAM.scala:55:75: This catches all Throwables. If this is really intended, use `case _ : Throwable` to clear this warning.
[warn]       case Some(x: JsString) => try { BigInt(x.as[String]) } catch { case _ => return None }
[warn]                                                                           ^

[ingallsj]

Thanks for the approval, @edwardcwang! Can you, or somebody with write access, please merge this?