Adds support for 32 build servers

This commit extends 6128f84330c1bd5efea187f7ff477b53e0b7e32e to
complete support for 32 bit Linux servers for generating nightly orcc
builds.

1. The download of p2-admin is now sensitive to 32/64 bit
   architecture.

2. build.properties in pdeconfig now builds for both x86 and x86_64.