Coverity: fix high impact issues

src/Main/MainCmd.cpp

@@ -138,8 +138,12 @@ int main( int argc, char ** argv )
     // Destruction phase ===========================================================
     Console().Log("FreeCAD terminating...\n");
 
-    // close open documents
-    App::GetApplication().closeAllDocuments();
+    try {
+        // close open documents
+        App::GetApplication().closeAllDocuments();
+    }
+    catch(...) {
+    }
 
     // cleans up
     Application::destruct();

src/Main/MainPy.cpp

@@ -118,6 +118,7 @@ extern "C"
         Dl_info info;
         int ret = dladdr((void*)initFreeCAD, &info);
         if ((ret == 0) || (!info.dli_fname)) {
+            free(argv);
             PyErr_SetString(PyExc_ImportError, "Cannot get path of the FreeCAD module!");
             return;
         }

src/Mod/Drawing/App/FeatureViewSpreadsheet.cpp

@@ -180,7 +180,7 @@ App::DocumentObjectExecReturn *FeatureViewSpreadsheet::execute(void)
                 celltext = field.str();
             }
             // get colors, style, alignment and span
-            int alignment;
+            int alignment = 0;
             std::string bcolor = "none";
             std::string fcolor = "#" + hr.str() + hg.str() + hb.str();
             std::string textstyle = "";

src/Mod/Fem/App/AppFemPy.cpp

@@ -140,8 +140,7 @@ private:
         FemMeshObject *pcFeature = static_cast<FemMeshObject *>
             (pcDoc->addObject("Fem::FemMeshObject", file.fileNamePure().c_str()));
         pcFeature->Label.setValue(file.fileNamePure().c_str());
-        pcFeature->FemMesh.setValuePtr(mesh.get());
-        (void)mesh.release();
+        pcFeature->FemMesh.setValuePtr(mesh.release());
         pcFeature->purgeTouched();
 
         return Py::None();
@@ -175,8 +174,7 @@ private:
             FemMeshObject *pcFeature = static_cast<FemMeshObject *>
                 (pcDoc->addObject("Fem::FemMeshObject", file.fileNamePure().c_str()));
             pcFeature->Label.setValue(file.fileNamePure().c_str());
-            pcFeature->FemMesh.setValuePtr(mesh.get());
-            (void)mesh.release();
+            pcFeature->FemMesh.setValuePtr(mesh.release());
             pcFeature->purgeTouched();
         }
         catch(Base::Exception& e) {

src/Mod/PartDesign/Gui/ViewProviderPrimitive.cpp

@@ -56,7 +56,7 @@ PROPERTY_SOURCE(PartDesignGui::ViewProviderPrimitive,PartDesignGui::ViewProvider
 
 ViewProviderPrimitive::ViewProviderPrimitive()
 {
-    
+    previewFaceSet = 0;
 }
 
 ViewProviderPrimitive::~ViewProviderPrimitive()

src/Mod/Sketcher/Gui/ViewProviderSketch.cpp

@@ -2698,7 +2698,7 @@ void ViewProviderSketch::drawMergedConstraintIcons(IconQueue iconQueue)
 
     // Tracks all constraint IDs that are combined into this icon
     QString idString;
-    int lastVPad;
+    int lastVPad = 0;
 
     QStringList labels;
     std::vector<int> ids;