Fix lookup with HOSTALIASES set.

ares__read_line returns ARES_EOF when it reaches the end of the
file. This will happen every time when reading to the end of the
HOSTALIASES file. Unfortunately single_domain treats this error as
being fatal.

Signed-off-by: Mike Crowe <mac@mcrowe.com>

ares_search.c

@@ -287,7 +287,7 @@ static int single_domain(ares_channel channel, const char *name, char **s)
                 }
               free(line);
               fclose(fp);
-              if (status != ARES_SUCCESS)
+              if (status != ARES_SUCCESS && status != ARES_EOF)
                 return status;
             }
           else