upgrade 7.1.x -> 7.2.x

I am having problems upgrading from 7.1.2 to 7.2.1

are there any tools that account for the char handling change from 7.1
to 7.2

    in 7.1.3     select 'hello'::char;   works

    in 7.2.1     select 'hello'::char;   fails

I am ambivalent to the dataype change
all I need is a tool that converts datatype char unmodified to varchar
unmodified
but leaves char modified (char(1), char(2)) alone.

possibly someone who has dealt with this has a hacked pg_dump.

C.