Fix #55 remove excessive rs_fatal() calls.
Fix #55 remove excessive rs_fatal() calls.

Replace unnecessary fs_fatal() calls in emit.c with asserts.
These errors could only happen if rs_int_len() was broken, so don't
need runtime checks, asserts are sufficient.

This also involved slighly changing the logic to avoid compiler
warnings when assserts are omitted for release builds, which also made
the code a little more consistent.

dbaarda/librsync,librsync/librsync,dbaarda/librsync,sourcefrog/librsync,sourcefrog/librsync,dbaarda/librsync,sourcefrog/librsync,dbaarda/librsync,librsync/librsync,librsync/librsync,librsync/librsync,sourcefrog/librsync