[FEM] fix Z88 binary handling

- when the binary was not found, the function called the non-existing binary
- also push error message for Elmer and Z88 to the status info so that user gets feedback also when report view console is not shown
- uniform wording to 'binary'
- avoid unnecessary console output

src/Mod/Fem/femsolver/elmer/tasks.py

@@ -159,7 +159,8 @@ class Solve(run.Solve):
             if not self.aborted:
                 self._updateOutput(output)
         else:
-            self.report.error("ElmerSolver executable not found.")
+            self.report.error("ElmerSolver binary not found.")
+            self.pushStatus("Error: ElmerSolver binary has not been found!")
             self.fail()
 
     def _updateOutput(self, output):

src/Mod/Fem/femsolver/settings.py

@@ -87,14 +87,16 @@ def get_binary(name):
     Return the specific path set by the user in FreeCADs settings/parameter
     system if set or the default binary name if no specific path is set. If no
     path was found because the solver *name* is not supported ``None`` is
-    returned. This method does not check whether the binary actually exists
-    and is callable.
+    returned.
+    This method does not check whether the binary actually exists and is callable.
+    That check is done in DlgSettingsFem_Solver_Imp.cpp
 
     :param name: solver id as a ``str`` (see :mod:`femsolver.settings`)
     """
     if name in _SOLVER_PARAM:
         binary = _SOLVER_PARAM[name].get_binary()
-        FreeCAD.Console.PrintMessage('Solver binary path: {} \n'.format(binary))
+        if binary is not None:
+            FreeCAD.Console.PrintMessage('Solver binary path: {} \n'.format(binary))
         return binary
     else:
         FreeCAD.Console.PrintError(
@@ -236,7 +238,8 @@ class _SolverDlg(object):
                 "The binary has not been found. Full binary search path: {}\n"
                 .format(binary)
             )
-        FreeCAD.Console.PrintLog("Solver binary found path: {}\n".format(the_found_binary))
+        else:
+            FreeCAD.Console.PrintLog("Found solver binary path: {}\n".format(the_found_binary))
         return the_found_binary
 
     def get_cores(self):

src/Mod/Fem/femsolver/z88/tasks.py

@@ -104,7 +104,9 @@ class Solve(run.Solve):
         self.pushStatus("Get solver binary...\n")
         binary = settings.get_binary("Z88")
         if binary is None:
-            self.fail()  # a print has been made in settings module
+            self.pushStatus("Error: The z88r binary has not been found!")
+            self.fail()
+            return
 
         prefs = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Fem/Z88")
         solver = SOLVER_TYPES