Revert r4498 and fix #3305357 properly. The issue was two-fold: (1) the compress...

Revert r4498 and fix #3305357 properly.	 The issue was two-fold:  (1) the compress buffer allocated by	the Tight encoder was not large	enough,	and (2) Zlib 1.2.5 can	sometimes call deflate(..., Z_BLOCK) within the	body of	deflateParams(), so we	need to	check avail_in after calling checkCompressionLevel() to	ensure that there is still data left to compress before we call deflate() again.

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4617 3789f03b-4d11-0410-bbf8-ca57d06f2519