Tests: added missing proxy prerequisites.

geo_ipv6.t

diff --git a/geo_ipv6.t b/geo_ipv6.t
index 9f447c3..ace28db 100644
--- a/geo_ipv6.t
+++ b/geo_ipv6.t
@@ -22,7 +22,7 @@
 select STDERR; $| = 1;
 select STDOUT; $| = 1;
 
-my $t = Test::Nginx->new()->has(qw/http geo/)
+my $t = Test::Nginx->new()->has(qw/http geo proxy/)
 	->write_file_expand('nginx.conf', <<'EOF');
 
 %%TEST_GLOBALS%%

sub_filter_buffering.t

diff --git a/sub_filter_buffering.t b/sub_filter_buffering.t
index e7e132c..43cf97a 100644
--- a/sub_filter_buffering.t
+++ b/sub_filter_buffering.t
@@ -24,7 +24,7 @@
 select STDERR; $| = 1;
 select STDOUT; $| = 1;
 
-my $t = Test::Nginx->new()->has(qw/http sub/)->plan(2)
+my $t = Test::Nginx->new()->has(qw/http sub proxy/)->plan(2)
 	->write_file_expand('nginx.conf', <<'EOF');
 
 %%TEST_GLOBALS%%