MB-5988: better error message if sqlite3 missing

Change-Id: I103b145f652aab7f12472897e51e35bb4970d4d7
Reviewed-on: http://review.couchbase.org/18739
Reviewed-by: Bin Cui <bin.cui@gmail.com>
Tested-by: Steve Yen <steve.yen@gmail.com>

pump_transfer.py

@@ -7,6 +7,15 @@
 import sys
 import threading
 
+try:
+    import sqlite3
+except ImportError:
+    msg = "error: could not import sqlite3 module"
+    if sys.version_info[0] < 2 or sys.version_info[1] < 6:
+        msg = msg + "; later versions of python (>= 2.6)" + \
+            " ship the required versions of the sqlite3 module"
+    sys.exit(msg)
+
 import pump
 import pump_bfd
 import pump_csv