[#2207] Move pointer dereference inside null check

STACK Output:
bug: anti-simplify
model: |
  %cmp75 = icmp ne %struct.MsParam* %inpParam2, null, !dbg !1187
  -->  true
stack:
  - /home/kellerb/software/root-stack/irods/iRODS/server/re/src/reDataObjOpr.cpp:702:0
ncore: 1
core:
  - /home/kellerb/software/root-stack/irods/iRODS/server/re/src/reDataObjOpr.cpp:654:0
    - null pointer dereference