Revert "[SVACE Fix][WGID: 34553] Use proper IPV6 address size"

Revert "[SVACE Fix][WGID: 34553] Use proper IPV6 address size"

This reverts commit a9296842694e6a84173860bbd9cc40ff325e1b82.

str is a variable to store ipv6 address from /proc/net/if_inet6. The value doesn't include ':', so the length of ipv6 address in /proc/net/if_inet6 is 32.
e.g)
sh-3.2# cat if_inet6
00000000000000000000000000000001 01 80 10 80       lo
fe8000000000000034dc1afffe42080e 57 40 20 80    wlan0
fd000000000000006cab78fe232e6105 57 40 00 01    wlan0

Change-Id: I678c80822cff6c794a2ddce3f3b6395ecf1e278e