app.h: Always initialize AST_DECLARE_APP_ARGS().

This patch ensures that the struct defined by AST_DECLARE_APP_ARGS() is always
fully initialized.  I'm not sure if this fixes any real bugs, but it silences
a bunch of warnings from coverity, and is generally a good thing to do anyway.
........

Merged revisions 359452 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 359454 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@359456 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/app.h

@@ -452,7 +452,7 @@ int ast_app_group_list_unlock(void);
   ast_app_separate_args() will perform that function before parsing
   the arguments.
  */
-#define AST_DECLARE_APP_ARGS(name, arglist) AST_DEFINE_APP_ARGS_TYPE(, arglist) name
+#define AST_DECLARE_APP_ARGS(name, arglist) AST_DEFINE_APP_ARGS_TYPE(, arglist) name = { 0, }
 
 /*!
   \brief Define a structure type to hold an application's arguments.