Fix regression with /i caused by r303047

[ngie]

Summary

Fix regression with /i caused by r303047

'\n' was specifically added to -e arguments prior to r303047; restore
historical behavior, which fixes /i as shown in the testing section,
and fixes usr.sbin/etcupdate/preworld_test:main [*]

PR: 195929, 211399 [*]
MFC after: (1 month from 07/19/2016)
X-MFC with: r303047
Reported by: Jenkins
Sponsored by: EMC / Isilon Storage Division

Test Plan

• Base case:

% echo "www:*:80:80:World Wide Web Owner:/nonexistent:/usr/sbin/nologin" | sed -e '/:80:/i\
auditdistd:*:78:77::0:0:Auditdistd unprivileged user:/var/empty:/usr/sbin/nologin'
auditdistd:*:78:77::0:0:Auditdistd unprivileged user:/var/empty:/usr/sbin/nologin
www:*:80:80:World Wide Web Owner:/nonexistent:/usr/sbin/nologin
%

• etcupdate testcase:

% sudo kyua test preworld_test
preworld_test:main -> passed [0.171s]

Results file id is usr_tests_usr.sbin_etcupdate.20160730-061144-858882
Results saved to /root/.kyua/store/results.usr_tests_usr.sbin_etcupdate.20160730-061144-858882.db

1/1 passed (0 failed)
%

[ngie]

rS303572