remove spurious execute bits from source files (#1072)

diff --git a/ansible/environments/local/group_vars/all b/ansible/environments/local/group_vars/all
old mode 100755
new mode 100644
diff --git a/cmd/version.go b/cmd/version.go
old mode 100755
new mode 100644
diff --git a/tools/travis/docker/Dockerfile b/tools/travis/docker/Dockerfile
old mode 100755
new mode 100644