Add new API virDomainBlockPull* to headers

Set up the types for the block pull functions and insert them into the
virDriver structure definition.  Symbols are exported in this patch to
prevent
documentation compile failures.

* include/libvirt/libvirt.h.in: new API
* src/driver.h: add the new entry to the driver structure
* python/generator.py: fix compiler errors, the actual python bindings
* are
  implemented later
* src/libvirt_public.syms: export symbols
* docs/apibuild.py: Extend 'unsigned long' parameter exception to this
* API

generator.py

@@ -186,6 +186,7 @@ def enum(type, name, value):
 functions_failed = []
 functions_skipped = [
     "virConnectListDomains",
+    'virDomainGetBlockJobInfo',
 ]
 
 skipped_modules = {
@@ -202,6 +203,7 @@ skipped_types = {
      'virStreamEventCallback': "No function types in python",
      'virEventHandleCallback': "No function types in python",
      'virEventTimeoutCallback': "No function types in python",
+     'virDomainBlockJobInfoPtr': "Not implemented yet",
 }
 
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