squisher: Don't set the OTAPACKAGE name

Instead of setting the OTAPACKAGE name here, expect
OTAPACKAGE will be passed to us. This fixes an issue when
BUILD_NUMBER is defined in an environment with automated
builds.

Change-Id: I0634416e5332790d314f6a70313ea67821fd1331
diff --git a/tools/squisher b/tools/squisher
index ce94537..54498f2 100755
--- a/tools/squisher
+++ b/tools/squisher
@@ -23,15 +23,6 @@
 	exit 1
 fi
 
-if [ "$TARGET_BUILD_TYPE" = "debug" ]; then
-    OTAPACKAGE=$OUT/${TARGET_PRODUCT}_debug-ota-$TARGET_BUILD_VARIANT.$USER.zip
-elif [ "$TARGET_BUILD_VARIANT" = "userdebug" ]; then
-    OTAPACKAGE=$OUT/$TARGET_PRODUCT-ota-eng.$USER.zip
-elif [ "$TARGET_BUILD_VARIANT" = "user" ]; then
-    OTAPACKAGE=$OUT/$TARGET_PRODUCT-ota-eng.$USER.zip
-else
-    OTAPACKAGE=$OUT/$TARGET_PRODUCT-ota-$TARGET_BUILD_VARIANT.$USER.zip
-fi
 if [ ! -f "$OTAPACKAGE" ]; then
 	echo "$OTAPACKAGE doesn't exist!";
 	exit 1