Reduce the LockFileManager timeout, and provide unsafeRemoveLockFile

5 minutes is an eternity, so try to strike a better balance between
waiting long enough for any reasonable module build and not so long that
users kill the process because they think it's hanging.

Also give the client a way to delete the lock file after a timeout.

llvm-svn: 228603
diff --git a/llvm/lib/Support/LockFileManager.cpp b/llvm/lib/Support/LockFileManager.cpp
index 5b82c36..9ec52ac 100644
--- a/llvm/lib/Support/LockFileManager.cpp
+++ b/llvm/lib/Support/LockFileManager.cpp
@@ -186,8 +186,8 @@
   Interval.tv_sec = 0;
   Interval.tv_nsec = 1000000;
 #endif
-  // Don't wait more than five minutes for the file to appear.
-  unsigned MaxSeconds = 300;
+  // Don't wait more than one minute for the file to appear.
+  unsigned MaxSeconds = 60;
   bool LockFileGone = false;
   do {
     // Sleep for the designated interval, to allow the owning process time to
@@ -263,3 +263,7 @@
   // Give up.
   return Res_Timeout;
 }
+
+std::error_code LockFileManager::unsafeRemoveLockFile() {
+  return sys::fs::remove(LockFileName.str());
+}