SCTX-1766: Configurable timeout for stunnel

Imported from xen-api-libs-transitional.git
9e46fa5d7ae9c4d3f10e58fce968bcee91e5bbbc

Signed-off-by: Akshay <akshay.ramani@citrix.com>
Imported-by: John Else <john.else@citrix.com>

Resolve Merge Conflicts for clearwater-sp1-lcm
	stunnel/stunnel.ml

Signed-off-by: Zheng Chai <zheng.chai@citrix.com>
Merge pull request #164 from Zhengchai/HFX-1149

HFX-1149: Pick SCTX-1766: Configurable timeout for stunnel from creedence (7541b5a) to clearwater-sp1-lcm