Merge pull request #76 from aschnell/master

- call tune2fs when changing data mode for ext3 and ext4 root filesystem (bnc#886240)
fix a potential segfault in LvmVg::doCreate

actual effects depend on l->chunkSize()

LvmVg.cc:1677:40: warning: adding 'unsigned long long' to a string does not append to the string
      [-Wstring-plus-int]
                cmd += " --chunksize " + l->chunkSize();
                       ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
LvmVg.cc:1677:40: note: use array indexing to silence this warning
                cmd += " --chunksize " + l->chunkSize();
                                       ^
                       &               [               ]
silence struct/class decl/def mismatch warnings

Storage.cc:692:1: warning: 'DiskData' defined as a struct here but previously declared as a class [-Wmismatched-tags]
struct DiskData
^
../storage/Storage.h:198:1: note: did you mean struct here?
class DiskData;
^~~~~
struct
(C++11) fstream constructors accept std::string
Merge pull request #80 from roman-neuhauser/fstream-string-arg

(C++11) fstream constructors accept std::string
Merge pull request #79 from roman-neuhauser/struct-class-mismatch

silence struct/class decl/def mismatch warnings
Merge pull request #77 from roman-neuhauser/LvmVg-doCreate-segfault

fix a potential segfault in LvmVg::doCreate