configure.ac: be clearer whether man pages will be installed
configure.ac: be clearer whether man pages will be installed

Man pages are only built if pandoc is installed, but it's easy to miss

    checking for pandoc... no
    configure: WARNING: Required executable pandoc not found, man pages will not be built

in the middle of the 120 lines of configure output. This commit adds
an explicit "Man pages: yes/no" message to the end of configure
output.

Signed-off-by: Matthew Dempsky <f80d0ca101e967b50b730ddf8e8aca0de85e8df6@dempsky.org>

01org/tpm2.0-tools,01org/tpm2.0-tools,01org/tpm2.0-tools