tests/histedit-helpers.sh

setup: fix installing in a mingw environment

The addition, in 9a4adc76c88a, of a hack for the MSVC compiler class was
overwriting the original class for the Mingw32CCompiler class, leading to an
error when the HackedMingw32CCompiler is instantiated.

Differential Revision: https://phab.mercurial-scm.org/D329

fixbundle() {
    grep -v 'saving bundle' | grep -v 'saved backup' | \
        grep -v added | grep -v adding | \
        grep -v "unable to find 'e' for patching" | \
        grep -v "e: No such file or directory" | \
    cat
}