Fix clang + ccache build warnings

modules/python/src2/cv2.cpp

@@ -510,7 +510,7 @@ static bool pyopencv_to(PyObject* obj, double& value, const char* name = "<unkno
     (void)name;
     if(!obj || obj == Py_None)
         return true;
-    if(PyInt_CheckExact(obj))
+    if(!!PyInt_CheckExact(obj))
         value = (double)PyInt_AS_LONG(obj);
     else
         value = PyFloat_AsDouble(obj);
@@ -527,7 +527,7 @@ static bool pyopencv_to(PyObject* obj, float& value, const char* name = "<unknow
     (void)name;
     if(!obj || obj == Py_None)
         return true;
-    if(PyInt_CheckExact(obj))
+    if(!!PyInt_CheckExact(obj))
         value = (float)PyInt_AS_LONG(obj);
     else
         value = (float)PyFloat_AsDouble(obj);
@@ -623,7 +623,7 @@ static inline bool pyopencv_to(PyObject* obj, Point& p, const char* name = "<unk
     (void)name;
     if(!obj || obj == Py_None)
         return true;
-    if(PyComplex_CheckExact(obj))
+    if(!!PyComplex_CheckExact(obj))
     {
         Py_complex c = PyComplex_AsCComplex(obj);
         p.x = saturate_cast<int>(c.real);
@@ -638,7 +638,7 @@ static inline bool pyopencv_to(PyObject* obj, Point2f& p, const char* name = "<u
     (void)name;
     if(!obj || obj == Py_None)
         return true;
-    if(PyComplex_CheckExact(obj))
+    if(!!PyComplex_CheckExact(obj))
     {
         Py_complex c = PyComplex_AsCComplex(obj);
         p.x = saturate_cast<float>(c.real);
@@ -989,7 +989,7 @@ static bool pyopencv_to(PyObject *o, cv::flann::IndexParams& p, const char *name
                 const char* value = PyString_AsString(item);
                 p.setString(k, value);
             }
-            else if( PyBool_Check(item) )
+            else if( !!PyBool_Check(item) )
                 p.setBool(k, item == Py_True);
             else if( PyInt_Check(item) )
             {

modules/python/src2/cv2.cv.hpp

@@ -1158,7 +1158,7 @@ static PyObject* cvseq_map_getitem(PyObject *o, PyObject *item)
     if (i < 0)
       i += (int)cvseq_seq_length(o);
     return cvseq_seq_getitem(o, i);
-  } else if (PySlice_Check(item)) {
+  } else if (!!PySlice_Check(item)) {
     Py_ssize_t start, stop, step, slicelength, cur, i;
     PyObject* result;
 
@@ -1975,7 +1975,7 @@ struct dims
 
 static int convert_to_dim(PyObject *item, int i, dims *dst, CvArr *cva, const char *name = "no_name")
 {
-  if (PySlice_Check(item)) {
+  if (!!PySlice_Check(item)) {
     Py_ssize_t start, stop, step, slicelength;
     PySlice_GetIndicesEx((PySliceObject*)item, cvGetDimSize(cva, i), &start, &stop, &step, &slicelength);
     dst->i[i] = (int)start;