bitbake/codeparser: Ensure cached sheel entries return the correct dependencies

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake/lib/bb/codeparser.py

@@ -206,7 +206,7 @@ class ShellParser():
 
         if h in shellparsecache:
             self.execs = shellparsecache[h].execs
-            return
+            return self.execs
 
         try:
             tokens, _ = pyshyacc.parse(value, eof=True, debug=False)