brltty security and bug fix update

[3.7.2-4]

• use rpm macros more consistently
• add manual page for brltty.conf
• add more documentation
• install the default brltty-pm.conf to docdir only
• Resolves: #530554
• silence the postinstall scriptlet
• Resolves: #529163
  [3.7.2-3]
• escape rpm macros in the rpm change log
• remove bogus rpath from libbrlttybba.so (CVE-2008-3279, #457942)
• add dependencies to bind the subpackages from one build together
  [3.7.2-2]
• fix building with newer kernel-headers (#456247)
• do not strip debug info during install (#500545)
• Resolves: rhbz #456247 #500545