Move mtree.5 to usr.sbin/nmtree.

Remove note that mtree 2.0 format files aren't supported.

usr.sbin/mtree/Makefile

@@ -6,7 +6,7 @@
 .PATH: ${.CURDIR}/../../usr.bin/cksum
 
 PROG=	fmtree
-MAN=	fmtree.8 mtree.5
+MAN=	fmtree.8
 SRCS=	compare.c crc.c create.c excludes.c misc.c mtree.c spec.c verify.c
 SRCS+=	specspec.c
 

usr.sbin/nmtree/Makefile

@@ -5,7 +5,7 @@
 .PATH: ${.CURDIR}/../../contrib/mtree
 
 PROG=		mtree
-MAN=		mtree.8
+MAN=		mtree.5 mtree.8
 SRCS=		compare.c crc.c create.c excludes.c getid.c misc.c mtree.c \
 		only.c spec.c specspec.c verify.c
 LDADD+=		-lmd -lutil

usr.sbin/nmtree/mtree.5

@@ -259,13 +259,6 @@ The
 entry format was added by
 .Nx .
 .Sh BUGS
-The
-.Fx
-implementation of mtree does not currently support
-the
-.Nm
-2.0
-format.
 The requirement for a
 .Dq #mtree
 signature line is new and not yet widely implemented.