bitbake: toaster: do not create duplicate HelpText objects

buildinfohelper code expects only one HelpText object per
build/variable/description.
Current code creates more than one such an object, which causes
toastergui to crash with this exception:
 MultipleObjectsReturned: get() returned more than one HelpText -- it returned 2!

Used git_or_create API to ensure that only one HelpText object is
created.

(Bitbake rev: e9b46803eb6f1f4044919abf90c8aeb3536e73ed)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: brian avery <avery.brian@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/ui/buildinfohelper.py

@@ -700,7 +700,6 @@ class ORMWrapper(object):
     def save_build_variables(self, build_obj, vardump):
         assert isinstance(build_obj, Build)
 
-        helptext_objects = []
         for k in vardump:
             desc = vardump[k]['doc']
             if desc is None:
@@ -711,10 +710,9 @@ class ORMWrapper(object):
             if desc is None:
                 desc = ''
             if len(desc):
-                helptext_objects.append(HelpText(build=build_obj,
-                    area=HelpText.VARIABLE,
-                    key=k,
-                    text=desc))
+                HelpText.objects.get_or_create(build=build_obj,
+                                               area=HelpText.VARIABLE,
+                                               key=k, text=desc)
             if not bool(vardump[k]['func']):
                 value = vardump[k]['v']
                 if value is None:
@@ -734,8 +732,6 @@ class ORMWrapper(object):
                 if len(varhist_objects):
                     VariableHistory.objects.bulk_create(varhist_objects)
 
-        HelpText.objects.bulk_create(helptext_objects)
-
 
 class MockEvent(object):
     """ This object is used to create event, for which normal event-processing methods can