[Crash-utility] crash version 4.0-2.11 is available

Adapted a number of proposed patches: - Badari Pulavarty of IBM's implentation of support for 2.6.14 ppc64 kernel's use of 4-level page tables. - Added a new "extensions" sub-directory for collecting crash command extension libaries; initially populated with the sample "echo.c" from the extend help page, along with a device-mapper related "dminfo.c" module from NEC. - Castor Fu of 3PAR's implementation of support for LKCD version 10, as well the handling of single-bit errors in LKCD compressed pages by trying out all possible single-bit errors. Also his fixes for better recognizing -fomit-frame-pointer kernel builds, a stronger defense against potential bogus processor numbers associated with tasks in dumpfiles, and a fix to re-allow crash builds for gcc 2.x compilers. Fix for potential "vmcore: initialization failed" fatal error during initializaton when using more than just a vmlinux and vmcore command line arguments. Fix for diskdump.c compile failures using gcc 2.96. Update to the x86_64 pseudo-backtrace code to show as a frame the RSP, RIP and name of the function causing a kernel-mode exception frame. Fix for the x86_64 pseudo-backtrace code to not neglect to show the user-mode exception frame when that task subsequently took a kernel-mode exception. Exported the load_extension() and unload_extension() functions so that they can be called from an extension library.