zdtm/ptrace_sic: set types for function arguments

I've updated Mr Jenkins to fc22 and can't compile zdtm tests:
cc -g -O2 -Wall -Werror -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0  -iquote ../../lib/arch/x86/include -I../../lib   ptrace_sig.c ../../lib/libzdtmtst.a   -o ptrace_sig
ptrace_sig.c: In function ‘child’:
ptrace_sig.c:33:5: error: type of ‘fd’ defaults to ‘int’ [-Werror=implicit-int]
 int child(fd)

Reported-by: Mr Jenkins
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm/live/static/ptrace_sig.c

@@ -30,7 +30,7 @@ void sig_chld_handler(int signo)
 	test_msg("Receive signal %d\n", signo);
 }
 
-int child(fd)
+int child(int fd)
 {
 	int ret = 0;
 	struct sigaction act = {