[v9_10] globally rename "delve" to "delv"

3817.	[func]		The "delve" command is now spelled "delv" to avoid
			a namespace collision with the Xapian project.
			[RT #35801]

(cherry picked from commit 2ae159b376)

bin/tests/system/dnssec/clean.sh

@@ -30,7 +30,7 @@ rm -f ns2/nsec3chain-test.db
 rm -f */example.bk
 rm -f dig.out.*
 rm -f rndc.out.*
-rm -f delve.out*
+rm -f delv.out*
 rm -f ns2/dlv.db
 rm -f ns3/multiple.example.db ns3/nsec3-unknown.example.db ns3/nsec3.example.db
 rm -f ns3/optout-unknown.example.db ns3/optout.example.db