Remove usage of backticks (#612)
Remove usage of backticks (#612)

There are several reason to always prefer the other form
for command output substiution.  See e.g.

  http://unix.stackexchange.com/questions/126927/have-backticks-i-e-cmd-in-sh-shells-been-deprecated

for a starting point.
ak3n/reason,cristianoc/reason,let-def/reason,yunxing/reason,facebook/reason,chenglou/reason,yunxing/reason,let-def/reason,facebook/reason,cristianoc/reason,cristianoc/reason,yunxing/reason,chenglou/reason,chenglou/reason,ak3n/reason,ak3n/reason,yunxing/reason,let-def/reason,facebook/reason,ak3n/reason