scons:reformat the custom boost and mapnik version checking cpp snippets, since on gcc 4.1.1 the existing formatting was causing 'no newline at end of file' warnings

SConstruct

@@ -296,12 +296,14 @@ def CheckBoost(context, version, silent=False):
     if not silent:
         context.Message('Checking for Boost version >= %s... ' % (version))
     ret = context.TryRun("""
+
 #include <boost/version.hpp>
 
 int main() 
 {
     return BOOST_VERSION >= %d ? 0 : 1;
 }
+
 """ % version_n, '.cpp')[0]
     if silent:
         context.did_show_result=1
@@ -310,14 +312,17 @@ def CheckBoost(context, version, silent=False):
 
 def GetBoostLibVersion(context):
     ret = context.TryRun("""
+
 #include <boost/version.hpp>
 #include <iostream>
 
 int main() 
 {
+
 std::cout << BOOST_LIB_VERSION << std::endl;
 return 0;
 }
+
 """, '.cpp')
     # hack to avoid printed output
     context.did_show_result=1
@@ -326,6 +331,7 @@ def GetBoostLibVersion(context):
 
 def GetMapnikLibVersion(context):
     ret = context.TryRun("""
+
 #include <mapnik/version.hpp>
 #include <iostream>
 
@@ -334,6 +340,7 @@ def GetMapnikLibVersion(context):
     std::cout << MAPNIK_VERSION << std::endl;
     return 0;
 }
+
 """, '.cpp')
     # hack to avoid printed output
     context.did_show_result=1