beinstall.sh: Various shell scripting improvements

[bcr]

Summary

This patch does the following:

1. Remove whitespace at the end of one line of license text
2. $var -> ${var}
3. use double quotes around variables to prevent globbing and word splits
4. Use ${@} instead of ${*} when looping over elements to prevent whitespace problems
5. Instead of [ expr1 -o expr2 ] use [expr1] || [expr2] as the former may have side effects
6. Save a pipe by using awk's / / functionality to search for a string instead of using grep piped to awk

Test Plan

Check output of beinstall.sh