Fix minor issues on the TV grabber TVMmaze

Syntax warnig during installation:
/tvmaze/utils.py:45: SyntaxWarning: "is not" with a literal. Did you mean "!="?

Create correct path to the cache file:
Use 'cachedir' to create the cahe folder, if it does not exits.

(cherry picked from commit 116a715)

mythtv/bindings/python/tvmaze/utils.py

@@ -42,7 +42,7 @@ def get_data(self):
 
 
 def strip_tags(html):
-    if html is not None and html is not "":
+    if html is not None and html != "":
         s = MLStripper()
         s.feed(html)
         return s.get_data()

mythtv/programs/scripts/metadata/Television/tvmaze.py

@@ -501,7 +501,7 @@ def main():
             confdir = os.path.join(confdir, '.mythtv')
         cachedir = os.path.join(confdir, 'cache')
         if not os.path.exists(cachedir):
-            os.makedirs(cachepath)
+            os.makedirs(cachedir)
         if sys.version_info[0] == 2:
             cache_name = os.path.join(cachedir, 'py2tvmaze')
         else: