Merging r294431:

------------------------------------------------------------------------
r294431 | mgorny | 2017-02-08 01:57:32 -0800 (Wed, 08 Feb 2017) | 7 lines

[test] Fix hard_link_count test to account for fs with dir nlink==1

Filesystems are not required to maintain a hard link count consistent
with number of subdirectories. For example, on btrfs all directories
have nlink==1. Account for that in the test.

Differential Revision: https://reviews.llvm.org/D29706
------------------------------------------------------------------------

llvm-svn: 295214