Rename tmp files

Bugreport handling apps know how to filter out .tmp files but not
*.tmp.[ext] files. Fix by moving tmp to the end.

Fixes: 148863019
Test: take bugreport, check /bugreports to verify all tmp files have
.tmp suffix
Test: atest dumpstate_test

Change-Id: I559cef85e5ff5f8a463038b4e4ebfd48063bb39f