Copy the entire zero-separated DNS seach domain string.

The DNS search string contains zeros as domain separator. The resolver
code erroneously used strlcpy(), which resulted in only the first domain
to be copied. The code uses pointers into this string to access the
individual domains. Since the structure is zero-initialized, this bug only
resulted in zero-length domains instead of accessing unitialized memory.

BUG: 27312811
Change-Id: Ia9d066c405dfcc5e82d6766d93ead2ce574e7b0d
(cherry picked from commit 0967fc7e)