Bug#139159: dpkg-source has no case insensitivity for some fields

[Adam Heath <doogie@brainfood.com>]

Package: dpkg-dev
Version: 1.9.19
Severity: minor

            if (m/^Source$/) { &setsourcepackage; }
            elsif (m/^(Standards-Version|Origin|Maintainer|Uploaders)$/) { $f{$_}= $v; }
            elsif (m/^Build-(Depends|Conflicts)(-Indep)?$/i) { $f{$_}= $v; }
            elsif (s/^X[BC]*S[BC]*-//i) { $f{$_}= $v; }
            elsif (m/^(Section|Priority|Files|Bugs)$/ || m/^X[BC]+-/i) { }
            elsif (m/^(Standards-Version|Origin|Maintainer|Uploaders)$/) { $f{$_}= $v; }

Note the lack of /i on some of those lines.  They should all consistently
ignore case.