Fix wrong wfree() use

There is a bug which happens when one modifies the "Initial Workspace" in the
"Attributes..." menu. Upon saving the change wmaker segfaults.

Commit ad373ef0dd ("WindowMaker: New function wGetWorkspaceNumber")
used wfree() in variables which were not wmalloc'ed. Fix this.

src/session.c

@@ -543,8 +543,6 @@ void wSessionRestoreLastWorkspace(WScreen * scr)
 	/* Get the workspace number for the workspace name */
 	w = wGetWorkspaceNumber(scr, value);
 
-	wfree(value);
-
 	if (w != scr->current_workspace && w < scr->workspace_count)
 		wWorkspaceChange(scr, w);
 }

src/wdefaults.c

@@ -455,8 +455,6 @@ int wDefaultGetStartWorkspace(WScreen * scr, char *instance, char *class)
 	/* Get the workspace number for the workspace name */
 	w = wGetWorkspaceNumber(scr, tmp);
 
-	wfree(value);
-
 	return w;
 }