Android camera qcom HAL doesn't like it when no consumer usage bits are set. Set a usage bit for preview BufferQueue.
Fixed bug which caused crash of GPU version of feature matcher in stitcher

The bug caused crash of GPU version of feature matcher in stitcher when
we use ORB features.
Added a TODO comment about changes which should be done in GpuMatcher::match
test knnMatch edge case with keypoints < knn
hopefully fixed Python tests
Merge pull request #3014 from vpisarev:fix_python_tests
Merge pull request #2968 from LeonidBeynenson:bugfix_crash_gpu_feature_matcher_in_stitcher
ocl: fix pyrUp perf test
Merge branch 'fix_androidcamera_preview_usage_bits' into 2.4
Android native camera rebuilt after sources update.
Merge pull request #3019 from alalek:ocl_fix_pyrUp_test
fix bug 3172
Merge branch '2.4' of https://github.com/Itseez/opencv into bug_3172_test
Merge branch 'bug_3172_test' of https://github.com/elmarb/opencv into bug_3172_test