fix bug for solaris.

dnsapi/deploy: remove POSIX character classes from sed/grep patterns

Solaris /usr/bin/sed and /usr/bin/grep parse [[:space:]] etc. as a
literal bracket set and silently mis-match. Replace with [ ]* for
JSON matching, a printf-tab bracket for user-input trimming, and
[0-9] for digits; also drop GNU-only sed -r/-E in rage4, selfhost
and selectel, and reuse _strip_blank_lines in byteplus_alb.

dnsapi/dns_poweradmin.sh

@@ -227,7 +227,7 @@ _poweradmin_rest() {
     return 1
   fi
 
-  if printf '%s' "$response" | grep -q '"success"[[:space:]]*:[[:space:]]*false'; then
+  if printf '%s' "$response" | grep -q '"success"[ ]*:[ ]*false'; then
     _err "API reported failure on $method $ep"
     _debug "Response: $response"
     return 1