Revert "Make weave build under go1.5; use our build flags for go get, and force stuff to be static."
Revert "Make weave build under go1.5; use our build flags for go get, and force stuff to be static."

This reverts commit 5860492a38d62801c38800282125202525aad870.

Although the build works under 1.4, this change had an unfortunate
impact (see #1412).

rade/weave,aaam/weave,rade/weave,weaveworks/weave,awanke/weave,beni55/weave,squaremo/weave,awh/weave,dpw/weave,awh/weave,paulbellamy/weave,dpw/weave,dpw/weave,dpw/weave,bboreham/weave,rade/weave,squaremo/weave,bboreham/weave,tomwilkie/weave,tomwilkie/weave,awh/weave,n054/weave,awanke/weave,squaremo/weave,bboreham/weave,squaremo/weave,beni55/weave,squaremo/weave,paulbellamy/weave,aaam/weave,weaveworks/weave,rade/weave,awanke/weave,aaam/weave,n054/weave,weaveworks/weave,bboreham/weave,bboreham/weave,beni55/weave,awanke/weave,paulbellamy/weave,dpw/weave,n054/weave,rade/weave,awh/weave,awanke/weave,awh/weave,tomwilkie/weave,n054/weave,weaveworks/weave,aaam/weave,beni55/weave,aaam/weave,beni55/weave,n054/weave,paulbellamy/weave,tomwilkie/weave,tomwilkie/weave