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

Signed-off-by: Adam Litke <agl@us.ibm.com>

generator.py

@@ -184,6 +184,8 @@ def enum(type, name, value):
 functions_failed = []
 functions_skipped = [
     "virConnectListDomains",
+    'virDomainBlockPull',
+    'virDomainGetBlockPullInfo',
 ]
 
 skipped_modules = {
@@ -198,6 +200,7 @@ skipped_types = {
      'virConnectDomainEventIOErrorCallback': "No function types in python",
      'virConnectDomainEventGraphicsCallback': "No function types in python",
      'virEventAddHandleFunc': "No function types in python",
+     'virDomainBlockPullInfoPtr': "Not implemented yet",
 }
 
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