tests: loop on short binary packet reads

Awesome bug goes like this:

let "c1" be the commit of the "good state" and "c2" be the commit
immediately after (in a bad state).  "t1" is the state of the tree in "c1"
and "t2" is the state of the tree in "c2"

In their natural states, we have this:

c1 -> t1 -> success
c1 -> t2 -> fail

However, if you take

c1 -> t1 -> patch to t2 -> success
c2 -> t2 -> patch to t1 -> fail

So t1 *and* t2 both succeed if the committed tree is c1, but both fail of
the committed tree is c2.

The difference?  c1 has a tag that points to it so the version number is
"1.2.10" whereas the version number for the unreleased c2 is
"1.4.10-1-gee486ab" -- a bit longer, breaks stuff in tests that try to
print stats.

1 files changed, 7 insertions, 3 deletions

diff --git a/t/binary.t b/t/binary.t
index adc30c0..504ddef 100755
--- a/t/binary.t
+++ b/t/binary.t
@@ -573,11 +573,15 @@ sub _handle_single_response {
     my $self = shift;
     my $myopaque = shift;
 
-    $self->{socket}->recv(my $response, ::MIN_RECV_BYTES);
-    Test::More::is(length($response), ::MIN_RECV_BYTES, "Expected read length");
+    my $hdr = "";
+    while(::MIN_RECV_BYTES - length($hdr) > 0) {
+        $self->{socket}->recv(my $response, ::MIN_RECV_BYTES - length($hdr));
+        $hdr .= $response;
+    }
+    Test::More::is(length($hdr), ::MIN_RECV_BYTES, "Expected read length");
 
     my ($magic, $cmd, $keylen, $extralen, $datatype, $status, $remaining,
-        $opaque, $ident_hi, $ident_lo) = unpack(::RES_PKT_FMT, $response);
+        $opaque, $ident_hi, $ident_lo) = unpack(::RES_PKT_FMT, $hdr);
     Test::More::is($magic, ::RES_MAGIC, "Got proper response magic");
 
     my $cas = ($ident_hi * 2 ** 32) + $ident_lo;