Reorder checks for clarity

Change-Id: I3b18f2dab7b4d7e874548c252730566b2df12798
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/184077
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

basic/source/comp/dim.cxx

@@ -63,13 +63,13 @@ SbiSymDef* SbiParser::VarDecl( SbiExprListPtr* ppDim, bool bStatic, bool bConst
     if( bWithEvents )
         pDef->SetWithEvents();
     TypeDecl( *pDef );
-    if( !ppDim && pDim )
+    if (ppDim)
+        *ppDim = std::move(pDim);
+    else if (pDim)
     {
         if(pDim->GetDims() )
             Error( ERRCODE_BASIC_EXPECTED, u"()"_ustr );
     }
-    else if( ppDim )
-        *ppDim = std::move(pDim);
     return pDef;
 }