[O] Date macro and file permission

[Michael Brand]

Hi all

Visiting a read-only file that uses the ~#+date:~ macro results in the
message "File mode specification error: (buffer-read-only #<killed
buffer>)" and a not properly initialized Org buffer. For example Org
indent does not indent and some faces show a wrong color. I tried
today's master branch and found the regression here

    commit 5f5d82ed516b7b385a9258271becbfa247e94af3
    Author: Nicolas Goaziou <address@hidden>
    Date:   Tue Nov 21 22:25:17 2017 +0100

        Remove second pass for macro expansion

Michael