glib-2.0: fix builds on fedora 17

glib-2.0: fix builds on fedora 17

Generally distros keep perl at /usr/bin/perl
Fedora 17 also has /bin/perl

this causes glib-2.0 build on such distros to put perl interpreter path in
the perl scripts as /bin/perl

But we set perl location for target as /usr/bin/perl

This mismatch of perl path causes failure of rootfs image creation
like this:

| error: Failed dependencies:
|       /bin/perl is needed by libglib-2.0-utils-2.30.3-r0.ppc603e
NOTE: package meta-toolchain-gmae-1.0-r7: task do_populate_sdk: Failed

[YOCTO #2304]

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