Fix cmake set_property in python bindings
Fix cmake set_property in python bindings

`SET_SOURCE_FILES_PROPERTIES(pfw.i PROPERTIES SWIG_FLAGS "-v" "-Wall"
"-Werror")` sets 2 variables:
 - `SWIG_FLAGS="-v"`
 - `-Wall="-Werror"`
which is obviously not what was wanted.

Replace by `SET_PROPERTY(SOURCE pfw.i PROPERTY SWIG_FLAGS "-v" "-Wall"
"-Werror")` that only sets `SWIG_FLAGS="-v -Wall -Werror"`.

Signed-off-by: Kevin Rocard <f6672397850e914591889d29dcaf9077eb1a8a4f@intel.com>

dbrageul/parameter-framework,Makohoek/parameter-framework,AdrienMQ/parameter-framework,miguelgaio/parameter-framework,soaresm/parameter-framework,clero/parameter-framework,dawagner/parameter-framework,clero/parameter-framework,anwarMov/parameter-framework,clero/parameter-framework,wzairix/parameter-framework,01org/parameter-framework,wzairix/parameter-framework,tcahuzax/parameter-framework,miguelgaio/parameter-framework,AdrienMQ/parameter-framework,AdrienMQ/parameter-framework,Makohoek/parameter-framework,dawagner/parameter-framework,sdnnfv/parameter-framework,geekboxzone/mmallow_external_parameter-framework,zchokri/parameter-framework,dbrageul/parameter-framework,mgaio/parameter-framework,android-ia/hardware_intel_parameter-framework,anwarMov/parameter-framework,wzairix/parameter-framework,zchokri/parameter-framework,tcahuzax/parameter-framework,sdnnfv/parameter-framework,tcahuzax/parameter-framework,geekboxzone/mmallow_external_parameter-framework,android-ia/hardware_intel_parameter-framework,mgaio/parameter-framework,soaresm/parameter-framework,miguelgaio/parameter-framework,dbrageul/parameter-framework,android-ia/hardware_intel_parameter-framework,zchokri/parameter-framework,geekboxzone/mmallow_external_parameter-framework,krocard/parameter-framework,Makohoek/parameter-framework,01org/parameter-framework,krocard/parameter-framework,krocard/parameter-framework,soaresm/parameter-framework,mgaio/parameter-framework,01org/parameter-framework,anwarMov/parameter-framework,dawagner/parameter-framework,sdnnfv/parameter-framework