Fix wrong variable name to make target hash

MR !1412 (merged) introduced a bug on the python configuration targets: !1412 (diffs). The issue is a typo on the variable name holding the path being hashed. This bug does not show up in the python bindings because the target name on those is set outside of this function. It also does not appear when only one python package is configured as the target is still unique (hash of an empty string). However, the problem does appear when several python packages are being configured (e.g. dune-codegen).

Since this got into %DUNE 2.10.0, we also need a back-port there too.

cmake/modules/DunePythonInstallPackage.cmake

@@ -516,7 +516,7 @@ function(dune_python_configure_package)
 
     # Add a custom target that globally installs this package if requested
     if (NOT PYPKGCONF_INSTALL_TARGET)
-      string(MD5 path_hash "${PYCONFBIND_FULLPATH}")
+      string(MD5 path_hash "${PYPKGCONF_PATH}")
       set(PYPKGCONF_INSTALL_TARGET "install_python_${path_hash}")
     endif()