foamFormatConvert: Fixed region handling for lagrangian data

applications/utilities/miscellaneous/foamFormatConvert/foamFormatConvert.C

@@ -364,9 +364,8 @@ int main(int argc, char *argv[])
 
 
         // Check for lagrangian
-        stringList lagrangianDirs
+        const fileName lagrangianDir
         (
-            1,
             fileHandler().filePath
             (
                 runTime.timePath()
@@ -374,6 +373,11 @@ int main(int argc, char *argv[])
               / cloud::prefix
             )
         );
+        stringList lagrangianDirs
+        (
+            lagrangianDir == fileName::null ? 0 : 1,
+            lagrangianDir
+        );
 
         combineReduce(lagrangianDirs, uniqueEqOp());
 
@@ -394,7 +398,7 @@ int main(int argc, char *argv[])
                     (
                         IOobject
                         (
-                            polyMesh::defaultRegion,
+                            regionName,
                             runTime.timeName(),
                             runTime,
                             Foam::IOobject::MUST_READ