HYD-2197 Increase prompt timout in install.exp
HYD-2197 Increase prompt timout in install.exp

Surprisingly enough, 300s was not enough and the installer stdin
drain was happening after we started emiting our answers to prompts
that actually didn't come yet.  So wait longer before timing out and
starting to emit those.

Signed-off-by: Brian J. Murrell <2a8f564cbb80211e19c0a14fed38a451599c042f@intel.com>
Change-Id: I999e1acfa0b1db8b85f666e2978acc5e963426f6

intel-hpdd/intel-manager-for-lustre,intel-hpdd/intel-manager-for-lustre,intel-hpdd/intel-manager-for-lustre