[sr-dev] [kamailio/kamailio] xmlrpc: compiler warnings in trunk and 5.1 (#1312)

CentOS Linux release 7.4.1708 (Core)

``` CC (gcc) [M xmlrpc.so] xmlrpc.o xmlrpc.c: In function 'set_fault': xmlrpc.c:894:2: warning: implicit declaration of function 'vsnprintf' [-Wimplicit-function-declaration] vsnprintf(buf, REASON_BUF_LEN, fmt, ap); ^ xmlrpc.c: In function 'print_value': xmlrpc.c:1024:4: warning: implicit declaration of function 'snprintf' [-Wimplicit-function-declaration] body.len = snprintf(buf, 256, "%f", va_arg(*ap, double)); ^ xmlrpc.c:1024:15: warning: incompatible implicit declaration of built-in function 'snprintf' [enabled by default] body.len = snprintf(buf, 256, "%f", va_arg(*ap, double)); ^ ```