Add missing HEADER_OS_VERSION header.

[aontas]

No description provided.

[aontas]

Added header I missed in #651.

[codecov]

Codecov Report

Merging #653 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##             master     #653      +/-   ##
============================================
- Coverage     52.86%   52.85%   -0.01%     
  Complexity     1676     1676              
============================================
  Files           131      131              
  Lines         10147    10148       +1     
  Branches       1408     1408              
============================================
  Hits           5364     5364              
- Misses         4340     4341       +1     
  Partials        443      443

Impacted Files	Coverage Δ	Complexity Δ
Parse/src/main/java/com/parse/ParsePlugins.java	42.85% <0%> (-0.45%)	12 <0> (ø)

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[rogerhu]

Thanks.