Downgrade some LOG_ERR messages in the address/* tests to warnings

Fixes bug 29530, where the LOG_ERR messages were occurring when
we had no configured network, and so we were failing the unit tests
because of the recently-merged #28668.

Commit message edited by teor:

We backported 28668 and released it in 0.3.5.8.
This commit backports 29530 to 0.3.5.

Fixes bug 29530 in Tor 0.3.5.8.

src/test/test_address.c

@@ -744,7 +744,7 @@ test_address_get_if_addrs_list_internal(void *arg)
 
   (void)arg;
 
-  results = get_interface_address_list(LOG_ERR, 1);
+  results = get_interface_address_list(LOG_WARN, 1);
 
   tt_ptr_op(results, OP_NE, NULL);
   /* When the network is down, a system might not have any non-local
@@ -775,7 +775,7 @@ test_address_get_if_addrs_list_no_internal(void *arg)
 
   (void)arg;
 
-  results = get_interface_address_list(LOG_ERR, 0);
+  results = get_interface_address_list(LOG_WARN, 0);
 
   tt_ptr_op(results, OP_NE, NULL);
   /* Work even on systems with only internal IPv4 addresses */
@@ -986,7 +986,7 @@ test_address_get_if_addrs(void *arg)
 
   (void)arg;
 
-  rv = get_interface_address(LOG_ERR, &addr_h);
+  rv = get_interface_address(LOG_WARN, &addr_h);
 
   /* When the network is down, a system might not have any non-local
    * non-multicast IPv4 addresses, not even internal ones.