configure.ac: fix some broken AM_CONDITIONALs

These AM_CONDITIONALs forgot to include the "test" executable,
resulting in output like this:

    ./configure: line 8718: no: command not found

From open-mpi/ompi@f21c349bcb3f7c322805d505484951642d1c7965
Merge pull request #1 from jsquyres/topic/am-conditional-fixes

configure.ac: fix some broken AM_CONDITIONALs