scripts/get_maintainer.pl: Correctly CC the maintainers

The current script is setting $email_remove_duplicates to 1 by default, on
complex patch (see [1]), this will result to ommitting randomly some
maintainers.

This is because, the script will:
    1) Get the list of maintainers of the file (incidentally all the
       maintainers in "THE REST" role are added). If the email address already
       exists in the global list, skip it. => The role will be lost
    2) Filter the list to remove the entry with "THE REST" role

So if a maintainers is marked with "THE REST" role on the first file and
actually be an x86 maintainers on the script, the script will only retain
the "THE REST" role. During the filtering step, this maintainers will
therefore be dropped.

This patch fixes this by setting $email_remove_duplicates to 0 by default.
The new behavior of the script will be:
    1) Append the list of maintainers for every file
    2) Filter the list to remove the entry with "THE REST" role
    3) Remove duplicated email address

Example:

Patch: https://patches.linaro.org/41083/

Before the patch:

Daniel De Graaf <dgdegra@tycho.nsa.gov>
Ian Jackson <ian.jackson@eu.citrix.com>
Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Ian Campbell <ian.campbell@citrix.com>
Wei Liu <wei.liu2@citrix.com>
George Dunlap <george.dunlap@eu.citrix.com>
xen-devel@lists.xen.org

After the patch:

Daniel De Graaf <dgdegra@tycho.nsa.gov>
Ian Jackson <ian.jackson@eu.citrix.com>
Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Ian Campbell <ian.campbell@citrix.com>
Wei Liu <wei.liu2@citrix.com>
Stefano Stabellini <stefano.stabellini@citrix.com>
Tim Deegan <tim@xen.org>
Keir Fraser <keir@xen.org>
Jan Beulich <jbeulich@suse.com>
George Dunlap <george.dunlap@eu.citrix.com>
xen-devel@lists.xen.org

[1] http://lists.xenproject.org/archives/html/xen-devel/2014-11/msg00060.html

Signed-off-by: Julien Grall <julien.grall@linaro.org>
CC: Don Slutz <dslutz@verizon.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

scripts/get_maintainer.pl

@@ -35,7 +35,7 @@
 my $email_git_since = "1-year-ago";
 my $email_hg_since = "-365";
 my $interactive = 0;
-my $email_remove_duplicates = 1;
+my $email_remove_duplicates = 0;
 my $email_use_mailmap = 1;
 my $email_drop_the_rest_supporter_if_supporter_found = 1;
 my $output_multiline = 1;