plug leak if there happens to be an error reading an arg

src/os/solaris/solaris_sigar.c

@@ -751,6 +751,7 @@ int sigar_proc_args_get(sigar_t *sigar, sigar_pid_t pid,
             if (argvp != argvb) {
                 free(argvp);
             }
+            sigar_proc_args_destroy(sigar, procargs);
             return errno;
         }