Don't truncate ${USER} when generating ro.build.fingerprint

We have removed the 92 character limit on ro.build.fingerprint, so
there is no longer a reason to truncate ${USER} when generating
fingerprints.

Bug: 34954705
Test: boot bullhead and observe non-truncated username
Change-Id: If79bf1d5372f709c9c1725f860bc61b99e830751
diff --git a/core/Makefile b/core/Makefile
index 2389698..912bf88 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -188,9 +188,7 @@
 # The string used to uniquely identify the combined build and product; used by the OTA server.
 ifeq (,$(strip $(BUILD_FINGERPRINT)))
   ifneq ($(filter eng.%,$(BUILD_NUMBER)),)
-    # Trim down BUILD_FINGERPRINT: the default BUILD_NUMBER makes it easily exceed
-    # the Android system property length limit (PROPERTY_VALUE_MAX=92).
-    BF_BUILD_NUMBER := $(shell echo $${USER:0:6})$(shell $(DATE) +%m%d%H%M)
+    BF_BUILD_NUMBER := $(USER)$(shell $(DATE) +%m%d%H%M)
   else
     BF_BUILD_NUMBER := $(BUILD_NUMBER)
   endif