Only show the welcome flow if we haven't shown it already
Only show the welcome flow if we haven't shown it already

This was missed in https://github.com/desktop/desktop/pull/1087.
hjobrien/desktop,shiftkey/desktop,gengjiawen/desktop,say25/desktop,hjobrien/desktop,artivilla/desktop,kactus-io/kactus,desktop/desktop,desktop/desktop,BugTesterTest/desktops,gengjiawen/desktop,j-f1/forked-desktop,gengjiawen/desktop,say25/desktop,shiftkey/desktop,shiftkey/desktop,artivilla/desktop,say25/desktop,j-f1/forked-desktop,hjobrien/desktop,gengjiawen/desktop,j-f1/forked-desktop,BugTesterTest/desktops,say25/desktop,kactus-io/kactus,kactus-io/kactus,hjobrien/desktop,kactus-io/kactus,BugTesterTest/desktops,j-f1/forked-desktop,desktop/desktop,BugTesterTest/desktops,artivilla/desktop,desktop/desktop,artivilla/desktop,shiftkey/desktop