Promiscuous regex for OSX version check in InstallAgent.sh and InstallServer.sh

[K.Lange]

The following code in src/Install[Agent|Server].sh needs to be changed, specifically the reggae used for determining Product version. 

The expression is far too promiscuous, not evaluating as expected, and failing on OS X Yosemite (10.10.x).

        # Creating for <= 10.4

        /usr/bin/sw_vers 2>/dev/null| grep "ProductVersion" | grep -E "10.2.|10.3|10.4" > /dev/null 2>&1

Instead should be

        # Creating for <= 10.4

        /usr/bin/sw_vers 2>/dev/null| grep "ProductVersion" | awk '{ print $2 }' | grep -E "^10\.[1234]\." > /dev/null 2>&1

[Mark Campbell]