physical-lock: Change vdl go generator to emit a single file.

Here's the old behavior.  In each vdl package, we generate *.go
files that match the *.vdl file names.

v.io/x/lib/foo/a.vdl
v.io/x/lib/foo/a.vdl.go # genfile
v.io/x/lib/foo/b.vdl
v.io/x/lib/foo/b.vdl.go #genfile

v.io/x/lib/bar/bar.vdl
v.io/x/lib/bar/bar.vdl.go # genfile

Here's the new behavior.  In each vdl package, we generate a
single <package name>.vdl.go file.

v.io/x/lib/foo/a.vdl
v.io/x/lib/foo/b.vdl
v.io/x/lib/foo/foo.vdl.go #genfile

v.io/x/lib/bar/bar.vdl
v.io/x/lib/bar/bar.vdl.go # genfile

The purpose of this change is to make it easier to deal with
initialization ordering issues in our generated code, and to make
the codegen simpler.  Those larger goals will be tackled in
subsequent CLs; this is the big one with lots of file moves and
deletions.

Note that the new vdl compiler will automatically delete any
old *.vdl.go files after it has successfully generated code.
That is only for the transitional step; we will remove that logic
after everyone has switched over.

Also removed the vdl -exts flag, which used to allow the user to
change the set of extensions to consider vdl files.  That was
used long ago to deal with experimental vdl features, and hasn't
been used in a while.

MultiPart: 6/7

Change-Id: I6670097d0efd31512aabf3fb2de365e3a1b43e0d
diff --git a/go/src/v.io/x/lock/lock.vdl.go b/go/src/v.io/x/lock/lock.vdl.go
index e4588f4..d036c66 100644
--- a/go/src/v.io/x/lock/lock.vdl.go
+++ b/go/src/v.io/x/lock/lock.vdl.go
@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // This file was auto-generated by the vanadium vdl tool.
-// Source: lock.vdl
+// Package: lock
 
 // Package lock defines the interface and implementation
 // for managing a physical lock.
@@ -37,7 +37,7 @@
 }
 
 func (m *LockStatus) FillVDLTarget(t vdl.Target, tt *vdl.Type) error {
-	if err := t.FromInt(int64((*m)), __VDLType_lock_v_io_x_lock_LockStatus); err != nil {
+	if err := t.FromInt(int64((*m)), __VDLType_v_io_x_lock_LockStatus); err != nil {
 		return err
 	}
 	return nil
@@ -93,9 +93,9 @@
 	vdl.Register((*LockStatus)(nil))
 }
 
-var __VDLType_lock_v_io_x_lock_LockStatus *vdl.Type = vdl.TypeOf(LockStatus(0))
+var __VDLType_v_io_x_lock_LockStatus *vdl.Type = vdl.TypeOf(LockStatus(0))
 
-func __VDLEnsureNativeBuilt_lock() {
+func __VDLEnsureNativeBuilt() {
 }
 
 const Locked = LockStatus(0)
diff --git a/go/src/v.io/x/lock/lock/errors.vdl.go b/go/src/v.io/x/lock/lock/main.vdl.go
similarity index 92%
rename from go/src/v.io/x/lock/lock/errors.vdl.go
rename to go/src/v.io/x/lock/lock/main.vdl.go
index d11a98d..bd17b5d 100644
--- a/go/src/v.io/x/lock/lock/errors.vdl.go
+++ b/go/src/v.io/x/lock/lock/main.vdl.go
@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // This file was auto-generated by the vanadium vdl tool.
-// Source: errors.vdl
+// Package: main
 
 package main
 
@@ -13,7 +13,7 @@
 	"v.io/v23/verror"
 )
 
-func __VDLEnsureNativeBuilt_errors() {
+func __VDLEnsureNativeBuilt() {
 }
 
 var (
diff --git a/go/src/v.io/x/lock/lockd/errors.vdl.go b/go/src/v.io/x/lock/lockd/main.vdl.go
similarity index 95%
rename from go/src/v.io/x/lock/lockd/errors.vdl.go
rename to go/src/v.io/x/lock/lockd/main.vdl.go
index ddf102b..030de5b 100644
--- a/go/src/v.io/x/lock/lockd/errors.vdl.go
+++ b/go/src/v.io/x/lock/lockd/main.vdl.go
@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // This file was auto-generated by the vanadium vdl tool.
-// Source: errors.vdl
+// Package: main
 
 package main
 
@@ -13,7 +13,7 @@
 	"v.io/v23/verror"
 )
 
-func __VDLEnsureNativeBuilt_errors() {
+func __VDLEnsureNativeBuilt() {
 }
 
 var (