cache: Don't try to expand __inherit_data

Trying to expand a variable which isn't a string doesn't make sense.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

lib/bb/cache.py

@@ -85,8 +85,8 @@ def flaglist(cls, flag, varlist, metadata, squash=False):
             return out_dict
 
     @classmethod
-    def getvar(cls, var, metadata):
-        return metadata.getVar(var, True) or ''
+    def getvar(cls, var, metadata, expand = True):
+        return metadata.getVar(var, expand) or ''
 
 
 class CoreRecipeInfo(RecipeInfoCommon):
@@ -142,7 +142,7 @@ def __init__(self, filename, metadata):
         self.rprovides_pkg    = self.pkgvar('RPROVIDES', self.packages, metadata)
         self.rdepends_pkg     = self.pkgvar('RDEPENDS', self.packages, metadata)
         self.rrecommends_pkg  = self.pkgvar('RRECOMMENDS', self.packages, metadata)
-        self.inherits         = self.getvar('__inherit_cache', metadata)
+        self.inherits         = self.getvar('__inherit_cache', metadata, expand=False)
         self.fakerootenv      = self.getvar('FAKEROOTENV', metadata)
         self.fakerootdirs     = self.getvar('FAKEROOTDIRS', metadata)
         self.fakerootnoenv    = self.getvar('FAKEROOTNOENV', metadata)