scripts/wrapper: fix wrong test when checking access to the reall tool

In C, the proper syntax for a bit-wise OR is a single '|', not two.

It worked so far because all was well:
- X_OK == 1
- R_OK||X_OK == 1
- the file we searched for had the x-bit set
-> access( file, R_OK||X_OK ) worked
- inicidentally, the file we searched for also had the r-bit set,
but we were not testing that in fact.

 # AVR32 specific configuration file

 config ARCH_avr32

     select ARCH_SUPPORTS_32

     select ARCH_DEFAULT_32

     select ARCH_USE_MMU

     select ARCH_DEFAULT_BE

     select ARCH_SUPPORT_ARCH

     select ARCH_SUPPORT_CPU

     select ARCH_SUPPORT_TUNE

     select ARCH_SUPPORT_FPU

      help

       The AVR32 architecture, as defined by:

         http://www.atmel.com/products/avr32