zstd: fix compilation with Solaris Studio

Without these changes, Solaris Studio (12.4) gives us "syntax error: empty
declaration" on these two lines.

contrib/python-zstandard/c-ext/compressionparams.c

@@ -136,7 +136,7 b' static void CompressionParameters_deallo'
 
 static Py_ssize_t CompressionParameters_length(PyObject* self) {
 	return 7;
-};
+}
 
 static PyObject* CompressionParameters_item(PyObject* o, Py_ssize_t i) {
 	CompressionParametersObject* self = (CompressionParametersObject*)o;

contrib/python-zstandard/c-ext/dictparams.c

@@ -42,7 +42,7 b' static void DictParameters_dealloc(PyObj'
 
 static Py_ssize_t DictParameters_length(PyObject* self) {
 	return 4;
-};
+}
 
 static PyObject* DictParameters_item(PyObject* o, Py_ssize_t i) {
 	DictParametersObject* self = (DictParametersObject*)o;