* gnu/installer/utils.scm (run-shell-command): Rename to...
(run-command): Remove call to 'call-with-temporary-output-file' and hop
through Bash. Expect COMMAND to be a list of strings rather than a
string.
* gnu/installer/final.scm (install-system): Turn INSTALL-COMMAND into a
list of strings and pass it to 'run-command'.
* gnu/installer/newt/page.scm (edit-file): Likewise.