MT#15803 Fix usage of HA features in 'ngcpcfg status'

`which $function` doesn't work as intended, commit
dc984aa2e7 in ngcpcfg-ha.git broke the HA features
in 'ngcpcfg status' therefore.

Change-Id: I2bb9ed9b3276e63fc6d127559df32ae229a43b33
(cherry picked from commit d7d48e15a1)

scripts/status

@@ -96,21 +96,21 @@ check_etc_state() {
 }
 
 check_push() {
-  if which execute_check_push &>/dev/null ; then
+  if type -p execute_check_push &>/dev/null ; then
     log_debug "execute_check_push function"
     execute_check_push
   fi
 }
 
 check_shared_storage() {
-  if which execute_check_shared_storage &>/dev/null ; then
+  if type -p execute_check_shared_storage &>/dev/null ; then
     log_debug "execute_check_shared_storage function"
     execute_check_shared_storage
   fi
 }
 
 check_remote() {
-  if which execute_check_remote &>/dev/null ; then
+  if type -p execute_check_remote &>/dev/null ; then
     log_debug "execute_check_remote function"
     execute_check_remote
   fi