bitbake meta-toolchain with gcc 4.5.1 failed

bitbake meta-toolchain with gcc 4.5.1 failed

Fixes bug [YOCTO #1386]

1) Add the following lines to conf/local.conf:

SDKGCCVERSION="4.5.1"
GCCVERSION="4.5.1"

2) bitbake meta-toolchain

The we will notice the error that sed can't find the directory:

${TMPDIR}/work-shared/gcc-${PV}/gcc-${PV}-${PR}

we had changed the name of S from gcc-${PV} to gcc-${PV}-${PR}, but didn't
update meta/recipes-devtools/gcc/gcc-common.inc, so fix S in gcc-common.inc
would make it work.

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>