Remove an improperly placed semicolon in order to solve the following
compiler error:

.../main.c:144:3: error: this 'if' clause does not guard... [-Werror=misleading-indentation]
    if (execl("/bin/busybox", "/bin/busybox", "md5sum", file, NULL));
    ^~
    .../main.c:145:4: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
    return NULL;
    ^~~~~~
    cc1: all warnings being treated as errors

Fixes #4723.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

luci2-io-helper: bugfix buckup script read timeout

Reading files from stdin will block for ever. The uhttpd is killing the
backup process after script_timeout.

Switching read to non blocking mode and add a waitpid for the slave
process does not end in a script_timeout anymore.

Signed-off-by: Florian Eckert <Eckert.Florian@googlemail.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

Signed-off-by: John Crispin <blogic@openwrt.org>