Luke Shumaker authored Jun 18, 2014 and Eli Schwartz committed Mar 21, 2018

 - db-functions: getpkgfile: The .sig file extension should be part of
   the filename parameter, not part of the message format string.

 - db-functions: arch_repo_modify: Shouldn't use ${action}
   string-interpolation in the message format string.  Since the
   entire message is a command, and we're using @Q to escape arguments
   anyway, go ahead and just construct the entire command as a single
   string that way, and feed it to '%s'.