contrib: fix gcc test suite on system without echo -e

Fix the use of quotes in contrib/gcc-test-suite/Makefile to solve the
problem where board.exp is incorrectly generated on some build systems
where 'echo -e' is not handled correctly.

Signed-off-by: Andy Gibbs <andyg1001@hotmail.co.uk>
[Yann E. MORIN: fix space damage, pretty-up the stuff]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 # dmalloc debug facility

 # depends on ! BACKEND

 config DEBUG_dmalloc

     bool

 choice

     bool

     prompt "dmalloc version"

 # Don't remove next line

 # CT_INSERT_VERSION_BELOW

 config DMALLOC_V_5_5_2

     bool

     prompt "5.5.2"

 endchoice

 config DMALLOC_VERSION

     string

 # Don't remove next line

 # CT_INSERT_VERSION_STRING_BELOW

     default "5.5.2" if DMALLOC_V_5_5_2