fix ISSUE-1142: fix compile instructions

FIX:
  https://github.com/control-center/serviced/issues/1142

DEMO:
```
# plu@plu-9: ls ~/mygo
ls: cannot access /home/plu/mygo: No such file or directory
# plu@plu-9: export GOPATH=~/mygo
# plu@plu-9: export PATH="$PATH:$GOPATH/bin"
# plu@plu-9: mkdir -p $GOPATH/{bin,pkg,src}
# plu@plu-9: mkdir -p $GOPATH/src/github.com/control-center
# plu@plu-9: cd $GOPATH/src/github.com/control-center
# plu@plu-9: git clone git@github.com:control-center/serviced
Cloning into 'serviced'...
remote: Counting objects: 32711, done.
remote: Compressing objects: 100% (149/149), done.
remote: Total 32711 (delta 68), reused 0 (delta 0)
Receiving objects: 100% (32711/32711), 22.29 MiB | 5.91 MiB/s, done.
Resolving deltas: 100% (21379/21379), done.
Checking connectivity... done.
# plu@plu-9: cd serviced
# plu@plu-9: make
go get github.com/tools/godep
go install github.com/tools/godep
/home/plu/mygo/bin/godep restore
touch .Godeps_restored
cd isvcs && make
make[1]: Entering directory `/home/plu/mygo/src/github.com/control-center/serviced/isvcs'
cp resources/logstash/logstash.conf.in resources/logstash/logstash.conf
make[1]: Leaving directory `/home/plu/mygo/src/github.com/control-center/serviced/isvcs'
cd web && make build_js
make[1]: Entering directory `/home/plu/mygo/src/github.com/control-center/serviced/web'
cat static/js/main.js static/js/controllers/BackupRestoreControl.js static/js/controllers/CeleryLogicControl.js static/js/controllers/DeployedAppsControl.js static/js/controllers/DeployWizard.js static/js/controllers/DevControl.js static/js/controllers/HostDetailsControl.js static/js/controllers/HostsControl.js static/js/controllers/HostsMapControl.js static/js/controllers/IsvcsControl.js static/js/controllers/LanguageControl.js static/js/controllers/LogControl.js static/js/controllers/LoginControl.js static/js/controllers/NavbarControl.js static/js/controllers/PoolsControl.js static/js/controllers/PoolsDetailsControl.js static/js/controllers/ServicesMapControl.js static/js/controllers/SubServiceControl.js > static/js/controlplane.js || rm -rf static/js/controlplane.js
makefile:46: WARNING: This is a scurrilous lie. We are not minifying anything.
cp static/js/controlplane.js static/js/controlplane.min.js
make[1]: Leaving directory `/home/plu/mygo/src/github.com/control-center/serviced/web'
go build -ldflags "-X main.Version 0.8.0 -X main.Giturl '' -X main.Gitcommit 5905a4c -X main.Gitbranch develop -X main.Date 'Mon Oct  6 20:12:13 UTC 2014' -X main.Buildtag 0"
go install -ldflags "-X main.Version 0.8.0 -X main.Giturl '' -X main.Gitcommit 5905a4c -X main.Gitbranch develop -X main.Date 'Mon Oct  6 20:12:13 UTC 2014' -X main.Buildtag 0"
# plu@plu-9: ls -l ~/mygo/bin/
total 25200
-rwxr-xr-x 1 plu plu  8820568 Oct  6 15:12 godep
-rwxr-xr-x 1 plu plu 16980757 Oct  6 15:13 serviced
```