Document the package change in installation procedures
Document the package change in installation procedures

The move from the affinity to psutil package affects the installation
procedure, and this patch modifies the INSTALL document accordingly.

Signed-off-by: Hrvoje Ribicic <be5828fca31f89218048bec4189e30a581aa65da@google.com>
Reviewed-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>

ganeti-github-testing/ganeti-test-1,onponomarev/ganeti,andir/ganeti,dimara/ganeti,leshchevds/ganeti,dimara/ganeti,grnet/snf-ganeti,ganeti-github-testing/ganeti-test-1,andir/ganeti,bitemyapp/ganeti,leshchevds/ganeti,grnet/snf-ganeti,ganeti/ganeti,mbakke/ganeti,leshchevds/ganeti,mbakke/ganeti,yiannist/ganeti,bitemyapp/ganeti,ganeti/ganeti,yiannist/ganeti,onponomarev/ganeti,mbakke/ganeti,apyrgio/ganeti,andir/ganeti,yiannist/ganeti,apyrgio/ganeti,ganeti/ganeti