main/stdtime/localtime: Fix warning introduced in r433720

The patch in r433720 caused a warning to be kicked back by gcc. It occurred
due to this check in unistd.h:

    if (__nbytes > __bos0 (__buf))
        return __read_chk_warn (__fd, __buf, __nbytes, __bos0 (__buf));

That is, if __nbytes is greater than the result of GCC's built-in object size
for the struct, we'll kick back a warning.

As it turns out, this is because there is an error in the code in the patch.
We are passing the address of the pointer to the struct, not iev, which is a
pointer to the struct. Hence, the number of bytes is probably going to be lot
larger than the number of bytes that make up a pointer! This patch changes
the code just read from the pointer to the struct - which fixes the warning.

ASTERISK-24917
........

Merged revisions 433743 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@433744 65c4cc65-6c06-0410-ace0-fbb531ad65f3