in preparation to kill --enable-verbose in configure.ac
convert modules that use VERBOSE-YES/NO (uppercase) env variable
to do things differently at compile time
Convert canvas to use SAL_INFO/SAL_WARN mechanism instead of its
home-grown 'verbose logging'.

Change-Id: I2898d2309d421457839e3cd7078166c6da919882
Reviewed-on: https://gerrit.libreoffice.org/17619Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>