Fix execution of platform shell commands on android

* Add missing functionality to the process launcher
* Fixup PATH environment variable to workaround an OS bug
* Add default shell path to the host info structure

Differential revision: http://reviews.llvm.org/D8009

llvm-svn: 231065
diff --git a/lldb/source/Host/android/HostInfoAndroid.cpp b/lldb/source/Host/android/HostInfoAndroid.cpp
index c5e91d7..de5bae7 100644
--- a/lldb/source/Host/android/HostInfoAndroid.cpp
+++ b/lldb/source/Host/android/HostInfoAndroid.cpp
@@ -33,3 +33,9 @@
     file_spec.GetDirectory() = HostInfoLinux::GetProgramFileSpec().GetDirectory();
     return (bool)file_spec.GetDirectory();
 }
+
+FileSpec
+HostInfoAndroid::GetDefaultShell()
+{
+    return FileSpec("/system/bin/sh", false);
+}