org: fix python execution with in-tree source and Swig4

* doc/org/.dir-locals.el.in, doc/org/init.el.in: Set the
SPOT_UNINSTALLED envvar, as we already do in the test suite.

doc/org/.dir-locals.el.in

@@ -10,6 +10,7 @@
 			      (concat "@abs_top_builddir@/bin"
 				      path-separator
 				      (getenv "PATH")))
+                      (setenv "SPOT_UNINSTALLED" "1")
 		      (setenv "PYTHONPATH"
 			      (concat "@abs_top_builddir@/python/.libs:"
 				      "@abs_top_builddir@/python:"

doc/org/init.el.in

@@ -95,6 +95,7 @@
 
 (setenv "PATH"
 	(concat "@abs_top_builddir@/bin" path-separator (getenv "PATH")))
+(setenv "SPOT_UNINSTALLED" "1")
 (setenv "PYTHONPATH"
 	(concat "@abs_top_builddir@/python/.libs:"
 		"@abs_top_builddir@/python:"