common: add quotes to satisfy kati/bash/make/whatever

* Honestly, I have no idea why this works. Or, to put it more
  precisely, why it works without this on _some_ devices and not
  others. All of a sudden?

* Without this patch I'm getting:
    /opt/out/14.1/build-cm_d2vzw-clobber.ninja is missing, regenerating...
    terminate called after throwing an instance of 'std::out_of_range'
      what():  basic_string::erase
    make: *** [build/core/ninja.mk:167: /opt/out/14.1/build-cm_d2vzw-clobber.ninja] Aborted (core dumped)

    #### make failed to build some targets (5 seconds) ####

Change-Id: I4bf43868bf7dfe13df57151ae3597246164cbebc

config/common.mk

@@ -11,7 +11,7 @@ TARGET_BOOTANIMATION_SIZE := $(shell \
 
 # get a sorted list of the sizes
 bootanimation_sizes := $(subst .zip,, $(shell ls vendor/cm/prebuilt/common/bootanimation))
-bootanimation_sizes := $(shell echo -e $(subst $(space),'\n',$(bootanimation_sizes)) | sort -rn)
+bootanimation_sizes := $(shell echo -e $(subst "$(space)",'\n',"$(bootanimation_sizes)") | sort -rn)
 
 # find the appropriate size and set
 define check_and_set_bootanimation