sb: Clean up using argparse. It is not available on CentOS.

Include the argparse package in the source and use if not available.

source-builder/pkg-config

@@ -29,13 +29,22 @@
 # POSSIBILITY OF SUCH DAMAGE.
 #
 
-import argparse
 import os
 import sys
 
 base = os.path.dirname(sys.argv[0])
 sys.path.insert(0, base + '/sb')
 
+try:
+    import argparse
+except:
+    sys.path.insert(0, base + '/sb/imports')
+    try:
+        import argparse
+    except:
+        print >> sys.stderr, "Incorrect Source Builder installation"
+        sys.exit(1)
+
 try:
     import pkgconfig
 except ImportError:

source-builder/sb/pkgconfig.py

@@ -34,7 +34,6 @@
 # provided by the full pkg-config so packages can configure and build.
 #
 
-import argparse
 import os
 import os.path
 import re