Fixes the following warnings while building rpm package:
*** WARNING: ./usr/src/debug/wmbusmeters-0.9.31-2.fc33.x86_64/src/meter_izar.cc is executable but has no shebang, removing executable bit
*** WARNING: ./usr/src/debug/wmbusmeters-0.9.31-2.fc33.x86_64/src/meters.cc is executable but has no shebang, removing executable bit
*** WARNING: ./usr/src/debug/wmbusmeters-0.9.31-2.fc33.x86_64/src/meters_common_implementation.h is executable but has no shebang, removing executable bit
*** WARNING: ./usr/src/debug/wmbusmeters-0.9.31-2.fc33.x86_64/src/units.cc is executable but has no shebang, removing executable bit
*** WARNING: ./usr/src/debug/wmbusmeters-0.9.31-2.fc33.x86_64/src/units.h is executable but has no shebang, removing executable bit
Signed-off-by: Damian Wrobel <dwrobel@ertelnet.rybnik.pl>