Fix setsector and setres not to wipe out concurrent updates

setsector() reads the sector, prompts for input, then writes back the
sector, triggering a generation oops.  Any updates made by other
threads while setsector() waits for input are wiped out, triggering a
seqno mismatch oops.

Same for setres().

src/lib/commands/setres.c

@@ -68,6 +68,7 @@ setres(void)
 	    amt = 100;
 	if (amt < 0)
 	    amt = 0;
+	check_sect_ok(&sect);
 	switch (char0) {
 	case 'i':
 	    if (sect.sct_own != 0)

src/lib/commands/setsect.c

@@ -68,6 +68,7 @@ setsector(void)
 	if (!p || !*p)
 	    return RET_SYN;
 	amt = atoi(p);
+	check_sect_ok(&sect);
 	switch (char0) {
 	case 'i':
 	    current = sect.sct_min;