log.c: fix translation markings

log.c: fix translation markings

The parse_options API expects an array of alternative usage lines
to which it automatically ads the language-appropriate "or" when
displaying.  Each of these options is marked for translation with N_
and then later translated when gettext is called on each element
of the array.

Since the N_ macro just expands to its argument, if two N_-marked
strings appear next to each other without being separated by anything
else such as a comma, the preprocessor will join them into one string.

In that case two separate strings get marked for translation, but at
runtime they have been joined into a single string passed to gettext
which then fails to get translated because the combined string was
never marked for translation.

Fix this by properly separating the two N_ marked strings with
a comma and removing the embedded "\n" and "   or:" that are
properly supplied by the parse_options API.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>