[PECOFF] Rename getSectionAlignment -> getSectionDefaultAlignment.

These fields are for /align option. Section alignment can be set per-section
basis with /section option too. In order to avoid name conflicts, rename the
existing identifiers to become more specific. No functionality change.

llvm-svn: 194160
diff --git a/lld/lib/ReaderWriter/PECOFF/PECOFFLinkingContext.cpp b/lld/lib/ReaderWriter/PECOFF/PECOFFLinkingContext.cpp
index 0a51b77..f8a6cd6 100644
--- a/lld/lib/ReaderWriter/PECOFF/PECOFFLinkingContext.cpp
+++ b/lld/lib/ReaderWriter/PECOFF/PECOFFLinkingContext.cpp
@@ -53,10 +53,10 @@
     return false;
   }
 
-  std::bitset<64> alignment(_sectionAlignment);
+  std::bitset<64> alignment(_sectionDefaultAlignment);
   if (alignment.count() != 1) {
     diagnostics << "Section alignment must be a power of 2, but got "
-                << _sectionAlignment << "\n";
+                << _sectionDefaultAlignment << "\n";
     return false;
   }