Remove renaming notice and symlinks for arcstat and arc_summary

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Colm Buckley <colm@tuatha.org>
Signed-off-by: Shengqi Chen <harry-chen@outlook.com>
Closes #16357
Closes #17712

cmd/Makefile.am

@@ -107,11 +107,6 @@ $(call SUBST,dbufstat,%D%/)
 $(call SUBST,zilstat,%D%/)
 arc_summary: %D%/arc_summary
 	$(AM_V_at)cp $< $@
-
-cmd-rename-install-exec-hook:
-	$(LN_S) -f arcstat $(DESTDIR)$(bindir)/zarcstat
-	$(LN_S) -f arc_summary $(DESTDIR)$(bindir)/zarcsummary
-INSTALL_EXEC_HOOKS += cmd-rename-install-exec-hook
 endif
 
 PHONY += cmd

cmd/arc_summary

@@ -1021,13 +1021,6 @@ def main():
     treated separately because they come with their own call.
     """
 
-    # notify user for upcoming renaming in 2.4.0
-    abs_path = os.path.abspath(sys.argv[0].strip())
-    script_name = os.path.basename(abs_path)
-    if script_name != "zarcsummary":
-        sys.stderr.write("Note: this script will be renamed to zarcsummary in ")
-        sys.stderr.write("zfs 2.4.0. Please migrate ASAP.\n")
-
     kstats = get_kstats()
 
     if ARGS.graph:

cmd/arcstat.in

@@ -768,13 +768,6 @@ def calculate():
 
 def main():
 
-    # notify user for upcoming renaming in 2.4.0
-    abs_path = os.path.abspath(sys.argv[0].strip())
-    script_name = os.path.basename(abs_path)
-    if script_name != "zarcstat":
-        sys.stderr.write("Note: this script will be renamed to zarcstat in ")
-        sys.stderr.write("zfs 2.4.0. Please migrate ASAP.\n")
-
     global sint
     global count
     global hdr_intr