manifest.c: ensure realloc_if_full() returns 1 or 0
This fixes an MSVC 2008 warning that I don't see with gcc 4.6.3-2:
warning C4047: 'return' :
'bool' differs in levels of indirection from 'line *'
More importantly, the truncation from pointer to 'unsigned char' would have
returned 0 if self->lines pointed to an address divisible by 0xFF, which causes
find_lines() to return MANIFEST_OOM. I was able to cause this to happen in a
trivial program with the gcc compiler.
'a' in d: True
d['a']: va
'b' in d: True
d['b']: vb
'c' in d: True
d['c']: vc
'd' in d: True
d['d']: vd
'a' in d: False
'b' in d: True
d['b']: vb
'c' in d: True
d['c']: vc
'd' in d: True
d['d']: vd
'e' in d: True
d['e']: ve
'b' in d: True
d['b']: vb2
'c' in d: True
d['c']: vc2
'd' in d: True
d['d']: vd
'e' in d: False
'f' in d: True
d['f']: vf
'b' in d: False
'c' in d: False
'd' in d: False
'e' in d: False
'f' in d: False