Merge branch 'jk/cvsimport-quoting' into maint-2.10

Author: gitster

git-cvsimport.perl

@@ -642,6 +642,7 @@ sub is_sha1 {
 
 sub get_headref ($) {
 	my $name = shift;
+	$name =~ s/'/'\\''/;
 	my $r = `git rev-parse --verify '$name' 2>/dev/null`;
 	return undef unless $? == 0;
 	chomp $r;