get_maintainer: fix perlcritic warnings

perlcritic is a standard checker for Perl Best Practices.  This patch
fixes most of the warnings in the get_maintainer script.  If kernel
programmers are going to have checkpatch they should write clean scripts
as well...

Bareword file handle opened at line 176, column 1.  See pages 202,204 of PBP.  (Severity: 5)
Two-argument "open" used at line 176, column 1.  See page 207 of PBP.  (Severity: 5)
Bareword file handle opened at line 207, column 5.  See pages 202,204 of PBP.  (Severity: 5)
Two-argument "open" used at line 207, column 5.  See page 207 of PBP.  (Severity: 5)
Bareword file handle opened at line 246, column 6.  See pages 202,204 of PBP.  (Severity: 5)
Two-argument "open" used at line 246, column 6.  See page 207 of PBP.  (Severity: 5)
Bareword file handle opened at line 258, column 2.  See pages 202,204 of PBP.  (Severity: 5)
Two-argument "open" used at line 258, column 2.  See page 207 of PBP.  (Severity: 5)
Expression form of "eval" at line 983, column 17.  See page 161 of PBP.  (Severity: 5)
Expression form of "eval" at line 985, column 17.  See page 161 of PBP.  (Severity: 5)
Subroutine prototypes used at line 1186, column 1.  See page 194 of PBP.  (Severity: 5)
Subroutine prototypes used at line 1206, column 1.  See page 194 of PBP.  (Severity: 5)

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>