check-spacing: do not kill C++-style comments

Our HACKING guide forbids these.
There's no point in exempting these from the spacing check
if their existence is against our coding style.

Note that the non-usage of these comments itself is not enforced
by syntax check, probably because of the need to implement a C parser.

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>

build-aux/check-spacing.pl

@@ -45,9 +45,6 @@ foreach my $file (@ARGV) {
         # Kill any quoted strings
         $data =~ s,"(?:[^\\\"]|\\.)*","XXX",g;
 
-        # Kill any C++ style comments
-        $data =~ s,//.*$,//,;
-
         next if $data =~ /^#/;
 
         # Kill contents of multi-line comments