bectl(8): Add -o flag to destroy to clean up the origin snapshot of BE

We can't predict when destruction of origin is needed, and currently we have
a precedent for not prompting for things. Leave the decision up to the user
of bectl(8) if they want the origin snapshot to be destroyed or not.

Emits a warning when -o isn't used and an origin snapshot is left to be
cleaned up, for the time being. This is handy when one drops the -o flag but
really did want to clean up the origin.

A couple of -e ignore's have been sprinkled around the test suite for places
that we don't care that the origin's not been cleaned up. -o functionality
tests will be added in the future, but are omitted for now to reduce
conflicts with work in flight to fix bits of the tests.

Reported by:	Shawn Webb
MFC after:	1 week

1 files changed, 11 insertions, 3 deletions

diff --git a/sbin/bectl/bectl.8 b/sbin/bectl/bectl.8
index daff7306b0dd..fce3d606b366 100644
--- a/sbin/bectl/bectl.8
+++ b/sbin/bectl/bectl.8
@@ -18,7 +18,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd December 25, 2018
+.Dd February 10, 2019
 .Dt BECTL 8
 .Os
 .Sh NAME
@@ -40,7 +40,7 @@
 .Ar beName@snapshot
 .Nm
 .Cm destroy
-.Op Fl F
+.Op Fl \&Fo
 .Brq Ar beName | beName@snapshot
 .Nm
 .Cm export
@@ -124,7 +124,7 @@ If the
 flag is given, a recursive boot environment will be made.
 .It Xo
 .Cm destroy
-.Op Fl F
+.Op Fl \&Fo
 .Brq Ar beName | beName@snapshot
 .Xc
 Destroys the given
@@ -136,6 +136,14 @@ snapshot without confirmation, unlike in
 Specifying
 .Fl F
 will automatically unmount without confirmation.
+.Pp
+By default,
+.Nm
+will warn that it is not destroying the origin of
+.Ar beName .
+The
+.Fl o
+flag may be specified to destroy the origin as well.
 .It Cm export Ar sourceBe
 Export
 .Ar sourceBe