Updated python to 3.7.4

Makefile

 all:
-	tar xf Python-3.7.3.tar.xz
-	cd Python-3.7.3 && ./configure --build=$(CLFS_TARGET) --prefix=/usr --enable-shared --with-system-expat --with-system-ffi --with-ensurepip=yes --enable-optimizations
-	$(MAKE) -C Python-3.7.3
+	tar xf Python-3.7.4.tar.xz
+	cd Python-3.7.4 && ./configure --build=$(CLFS_TARGET) --prefix=/usr --enable-shared --with-system-expat --with-system-ffi --with-ensurepip=yes --enable-optimizations
+	$(MAKE) -C Python-3.7.4
 	if [[ ! "$(BUILD_OPTIONS)" =~ no-tests ]] ; then \
-	    $(MAKE) -C Python-3.7.3 test EXTRATESTOPTS="-j 1 -u all,-urlfetch --timeout=3600" ; \
+	    $(MAKE) -C Python-3.7.4 test EXTRATESTOPTS="-j 1 -u all,-urlfetch --timeout=3600" ; \
 	fi
-	$(MAKE) -C Python-3.7.3 install
+	$(MAKE) -C Python-3.7.4 install
 	chmod -v 755 /usr/lib/libpython3.7m.so
 	chmod -v 755 /usr/lib/libpython3.so
 	ln -sfv pip3.7 /usr/bin/pip3
 	rm $(HOME)/.python_history
-	rm -rf Python-3.7.3
+	rm -rf Python-3.7.4