Clean up OOO_SHELL

...which is no longer used.  Also, use the detected BASH value in Makefile.in
instead of re-detecting there.  (Though setting SHELL in Makefile.in is likely
bogus anyway, cf. "this is overridden by solenv/gbuild/gubild.mk [...] i don't
know what needs the 'SHELL=bash' in top-level makefile",
<http://lists.freedesktop.org/archives/libreoffice/2013-March/048552.html> "Re:
need help with shell / configure.")

Change-Id: I09c8b5eb9fb1244321d1fb998bb78e458e8ebf37

Makefile.in

@@ -13,7 +13,7 @@ ifeq ($(MAKECMDGOALS),)
 MAKECMDGOALS:=all
 endif
 
-SHELL=/usr/bin/env bash
+SHELL=@BASH@
 SRCDIR := @SRC_ROOT@
 BUILDDIR := @BUILDDIR@
 

config_host.mk.in

@@ -427,7 +427,6 @@ export OOOP_GALLERY_PACK=@OOOP_GALLERY_PACK@
 export OOOP_SAMPLES_PACK=@OOOP_SAMPLES_PACK@
 export OOOP_TEMPLATES_PACK=@OOOP_TEMPLATES_PACK@
 export OOO_JUNIT_JAR=@OOO_JUNIT_JAR@
-export OOO_SHELL=@BASH@
 export OOO_VENDOR=@OOO_VENDOR@
 export OPENSSL_CFLAGS=$(gb_SPACE)@OPENSSL_CFLAGS@
 export OPENSSL_LIBS=$(gb_SPACE)@OPENSSL_LIBS@