Port provisioner scripts to updated framework

Updates all the example provisioner scripts to use the new functions
exposed by the VMBuilder class as an illustration of how best to use
them.

Also adds a wrapper fail() handler to ensure the cleanup of the script,
as well as the global cleanup, are run on an exception.

api-daemon/pvcapid/vmbuilder.py

@@ -99,13 +99,8 @@ class VMBuilder(object):
     def log_err(self, msg):
         log_err(None, msg)
 
-    def fail(self, msg):
-        self.log_err(msg)
-        try:
-            self.cleanup()
-        except Exception:
-            pass
-        raise ProvisioningError()
+    def fail(self, msg, exception=ProvisioningError):
+        fail(None, msg, exception=exception)
 
     #
     # Primary class functions; implemented by the individual scripts
@@ -693,6 +688,14 @@ def create_vm(
             # We don't care about fails during cleanup, log and continue
             log_warn(celery, f"Suberror during general cleanup script removal: {e}")
 
+    def fail_clean(celery, msg, exception=ProvisioningError):
+        try:
+            vm_builder.cleanup()
+            general_cleanup()
+        except Exception:
+            pass
+        fail(celery, msg, exception=exception)
+
     # Phase 4 - script: setup()
     #  * Run pre-setup steps
     current_stage += 1
@@ -705,7 +708,7 @@ def create_vm(
             vm_builder.setup()
     except Exception as e:
         general_cleanup()
-        fail(
+        fail_clean(
             celery,
             f"Error in script setup() step: {e}",
             exception=ProvisioningError,
@@ -727,7 +730,7 @@ def create_vm(
                 vm_schema = vm_builder.create()
         except Exception as e:
             general_cleanup()
-            fail(
+            fail_clean(
                 celery,
                 f"Error in script create() step: {e}",
                 exception=ProvisioningError,
@@ -775,7 +778,7 @@ def create_vm(
         with chroot(temp_dir):
             vm_builder.cleanup()
         general_cleanup()
-        fail(
+        fail_clean(
             celery,
             f"Error in script prepare() step: {e}",
             exception=ProvisioningError,
@@ -798,7 +801,7 @@ def create_vm(
         with chroot(temp_dir):
             vm_builder.cleanup()
         general_cleanup()
-        fail(
+        fail_clean(
             celery,
             f"Error in script install() step: {e}",
             exception=ProvisioningError,
@@ -818,7 +821,6 @@ def create_vm(
         with chroot(temp_dir):
             vm_builder.cleanup()
     except Exception as e:
-        general_cleanup()
         fail(
             celery,
             f"Error in script cleanup() step: {e}",