Fix typo in dns_name_copy-with-result.spatch
A typo introduced in f3f1cab0 prevents
execution of the dns_name_copy-with-result.spatch. The replacement
should end with semicolon not a colon:
plus: parse error:
File "cocci/dns_name_copy-with-result.spatch", line 28, column 23, charpos = 421
around = ':',
whole content = + dns_name_copy(E1, E2):