SELinux: add .gitignore files for dynamic classes

The SELinux dynamic class work in c6d3aaa4
creates a number of dynamic header files and scripts.  Add .gitignore files
so git doesn't complain about these.
Signed-off-by: NEric Paris <eparis@redhat.com>
Acked-by: NStephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: NJames Morris <jmorris@namei.org>

Documentation/dontdiff

@@ -65,6 +65,7 @@ aicdb.h*
 asm-offsets.h
 asm_offsets.h
 autoconf.h*
+av_permissions.h
 bbootsect
 bin2c
 binkernel.spec
@@ -95,12 +96,14 @@ docproc
 elf2ecoff
 elfconfig.h*
 fixdep
+flask.h
 fore200e_mkfirm
 fore200e_pca_fw.c*
 gconf
 gen-devlist
 gen_crc32table
 gen_init_cpio
+genheaders
 genksyms
 *_gray256.c
 ihex2fw

scripts/selinux/genheaders/.gitignore

+genheaders

security/selinux/.gitignore

+av_permissions.h
+flask.h